While President Donald Trump still has hundreds of key positions to fill that will shape his next four years in office, his Cabinet is mostly full.

Trump has 24 official members of his Cabinet, and 111 days after he became president, the Senate confirmed all of them. But there have been some changes since then.

In the nearly nine months since Trump took office, multiple high-level hires withdrew from the confirmation process, and several senior advisers have resigned, including former chief of staff Reince Priebus and former Health and Human Services Secretary Tom Price.

Meet who is now counseling Trump for the next four years:

Secretary of State: Rex Tillerson (confirmed)

Foto: source Skye Gould/Business Insider

Obama administration counterparts: Hillary Clinton, John Kerry

Duties: act as the top American diplomat, lead US foreign policy

Reactions: Tillerson has been praised for his business acumen and diplomatic missions negotiating deals for ExxonMobil, but roundly criticized for his close ties to Russian President Vladimir Putin, and Senators from both sides of the aisle have said he'll have difficult confirmation hearings because of their relationship. While Tillerson accepts humans are causing climate change and he supports the Paris agreement to limit emissions, environmentalists have taken issue with ExxonMobil's fierce lobbying promoting oil and gas.

Treasury Secretary: Steven Mnuchin (confirmed)

Foto: source Skye Gould/Business Insider

Obama administration counterparts: Timothy F. Geithner, Jack Lew

Duties: serve as the president's principal economic adviser, manage the public debt, set US tax and fiscal policy

Reactions: As Business Insider's Matt Turner writes, there's a long list of reasons why people might not like Trump's pick for Treasury secretary. Sens. Elizabeth Warren and Bernie Sanders skewered Mnuchin's status as a hedge fund manager who worked at a large financial institution like Goldman Sachs - two things Trump called out on the campaign trail, as well.

Defense Secretary: Gen. James Mattis (confirmed)

Foto: source Skye Gould/Business Insider

Obama administration counterparts: Robert M. Gates, Leon Panetta, Chuck Hagel, Ashton Carter

Duties: lead the military, serve as "deputy commander-in-chief"

Reactions: Marines consider Mattis a warrior and he is well-respected by other service members. He has come under fire in the past for controversial admissions, however, like when he said in 2005 that it was "fun to shoot some people." Still, senators on both sides of the aisle have praised the pick, though they would have to waive a law requiring service members to wait seven years before becoming Defense Secretary to provide checks and balances. Sen. Kirsten Gillibrand of New York said she won't vote to waive the requirement, but Mattis likely has enough votes to clinch the nomination.

Attorney General: Sen. Jeff Sessions (confirmed)

Foto: source Skye Gould/Business Insider

Obama administration counterparts: Mark Filip, Eric Holder, Loretta Lynch

Duties: act as the country's chief law enforcement officer, represent the US in court cases, provide the Executive Branch with formal and informal legal counsel and advice

Reactions: Sessions' consideration for a Cabinet position has revived allegations of racism that jeopardized his chance to become a federal district court judge in 1986, when a prosecutor testified Sessions called the NAACP and the ACLU "un-American." Incoming Senate Democratic Leader Chuck Schumer said he is "very concerned" about Sessions' civil rights record, a sentiment other liberals echoed. Many conservatives, meanwhile, applauded Trump's choice, with Republican senators saying they'd vote to confirm him.

Interior Secretary: Ryan Zinke (confirmed)

Foto: source Skye Gould/Business Insider

Obama administration counterparts: Ken Salazar, Sally Jewell

Duties: manage and conserve federal land and natural resources, oversee agencies including the National Park Service, Bureau of Land Management and United States Geological Survey

Reactions: Environmental groups expressed concern that while Zinke professes he wants to protect natural resources, his voting record shows his support for fossil fuel companies, particularly for coal mining on federal lands.

Secretary of Agriculture: Sonny Perdue (confirmed)

Foto: source Skye Gould/Business Insider

Obama administration counterpart: Tom Vilsack

Duties: direct the $155 billion Agriculture Department, which oversees farm subsidies, agriculture policy, and food stamps

Reactions: Perdue's appointment is largely a non-controversial one. Some environmental groups put out statements saying they were concerned he wouldn't protect drinking water or natural resources, but agricultural organizations seem pleased.

Commerce Secretary: Wilbur Ross (confirmed)

Foto: source Skye Gould/Business Insider

Obama administration counterparts: Gary F. Locke, John E. Bryson, Penny Pritzker

Duties: promote American commerce and businesses

Reactions: There hasn't been much opposition to Ross' appointment. Some critics did bring up his billionaire, insider status and the fact that his coal company oversaw the Sago Mine disaster that killed a dozen people in 2005.

Labor Secretary: Alexander Acosta (confirmed)

Foto: source Skye Gould/Business Insider

Obama administration counterparts: Hilda L. Solis, Thomas Perez

Duties: enforce labor laws, including ones involving unions and other business-citizen relations

UPDATE 2/15: Top Republicans in the Senate encouraged the White House to withdraw Andrew Puzder's nomination (Trump's first labor pick), due to concerns that he wouldn't receive the necessary votes for confirmation. Critics, notably labor unions, were concerned that Puzder would 'betray American workers' because he's said in the past that machines are the answer to rising wages - not raising the minimum wage. Some women also expressed disgust that Puzder said he "like[s] beautiful women eating burgers in bikinis," who star in the ads for Carl's Jr., the fast food chain Puzder heads as CKE CEO. He dropped out of the running on February 15, a day before his confirmation hearing.

Reactions to Acosta: After Puzder's polarizing pick, many on both sides of the aisle view Acosta as a sensible choice for the job. The AFL-CIO trade union said Acosta's nomination deserves "serious consideration." The Senate has confirmed him for other roles three times, so he was expected to sail through again, and did.

Health and Human Services Secretary: Don J. Wright (Acting)

Foto: source Skye Gould/Business Insider

Obama administration counterparts: Kathleen Sebelius, Sylvia Mathews Burwell

Duties: lead the Department of Health and Human Services, which oversees agencies like the FDA, CDC, NIH, and the Centers for Medicare & Medicaid Services

Reactions to Price: Since Price has repeatedly tried to repeal and replace the Affordable Care Act, is pro-life, against gay marriage, opposes gun control, and denies the overwhelming evidence that climate change is real, many progressives are outraged he will be overseeing some of the country's largest science and health agencies. Many Republicans, particularly those who want to nix Obamacare, applauded the choice.

Resignation: After sparking bipartisan outrage over the cost of his air travel, which Politico reported cost taxpayers more than $1 million, Price resigned on September 29. He used private planes for domestic travel and military jets for trips to Africa, Europe, and Asia, and prompted some lawmakers to scrutinize other Cabinet officials' air travel as well. Trump has yet to name a replacement, and Don J. Wright is serving as the acting secretary for the time being.

Housing and Urban Development Secretary: Dr. Ben Carson (confirmed)

Foto: source Skye Gould/Business Insider

Obama administration counterparts: Shaun Donovan, Julian Castro

Duties: increase home ownership, increase access to affordable housing free from discrimination

Reactions: House Democratic leader Nancy Pelosi called Carson a "disturbingly unqualified choice" since he's never worked specifically in housing or urban development, or held a government position. Other critics voiced similar concerns, also noting that Carson called fair housing policy "social engineering" in a 2015 opinion piece.

Transportation Secretary: Elaine Chao (confirmed)

Foto: source Skye Gould/Business Insider

Obama administration counterparts: Ray H. LaHood, Anthony R. Foxx

Duties: lead the US Department of Transportation, which includes the Federal Aviation Administration and the Federal Highway Administration

Reactions: Uber and Lyft both said they approve of the choice, since Chao has said she supports the gig economy. There hasn't been much opposition to Chao, especially because she's a well-known, respected figure with experience at the federal level.

Energy Secretary: Rick Perry (confirmed)

Foto: source Skye Gould/Business Insider

Obama administration counterparts: Steven Chu, Ernest Moniz

Duties: lead US energy policy and regulation, oversee the 17 national labs and American nuclear security

Reactions: Perry has said in the past he wants to eliminate the Department of Energy (though he also forgot its name), prompting supporters of the agency to question his appointment to lead it. Democrats also criticized Perry for sitting on the Board of Directors of the company behind the highly controversial Dakota Access Pipeline as an example of why he's unfit for the post.

Secretary of Education: Betsy DeVos (confirmed)

Foto: source Skye Gould/Business Insider

Obama administration counterparts: Arne Duncan, John King, Jr.

Duties: Lead the US Department of Education, manage federal financial aid policies, ensure equal access to education.

Reactions: While proponents of school vouchers have predictably lauded Trump's pick, its opponents have lambasted DeVos, arguing that the programs weaken public schools and fund private schools at taxpayers' expense. Teachers' unions have similarly criticized her for not understanding the public school landscape since she sent her children to private schools.

Secretary of Veterans Affairs: Dr. David J. Shulkin (confirmed)

Foto: source Skye Gould/Business Insider

Obama administration counterparts: Eric Shinseki, Robert A. McDonald

Duties: lead the agency that provides medical benefits and care for the nation's veterans through the VA's 1,233 health care facilities, manage the national cemeteries

Reactions: While Shulkin himself is not a veteran, his father was an Army captain and he was born on a military base. President Barack Obama nominated him to be under secretary for health at the VA after cleaning house following the 2014 scandal finding that the agency's wait times were excessively long, jeopardizing its care of veterans.

Homeland Security Secretary: Kirstjen Nielsen (awaiting Senate confirmation)

Foto: The Homeland Security Department's top job has been vacant since July, when John Kelly was given the chief of staff role after the ousting of his predecessor, Reince Priebus. source Skye Gould/Business Insider

Obama administration counterparts: Janet Napolitano, Rand Beers, Jeh Johnson

Duties: secure borders against illegal immigration, protect the president, respond to natural disasters, coordinate intelligence, counter terror threats. President George W. Bush created the Department of Homeland Security after 9/11.

Reactions: Nielsen is known for being a brusque enforcer of John Kelly's agenda in the West Wing, where her reportedly curt, no-nonsense manner caused some backlash among Trump aides. There wasn't much backlash to the appointment, because of Nielsen's considerable national security and cybersecurity expertise.

United Nations Ambassador: Gov. Nikki Haley (confirmed)

Foto: source Skye Gould/Business Insider

Obama administration counterparts: Susan Rice, Rosemary DiCarlo, Samantha Power

Duty: Advance US interests at the United Nations.

Reactions: Some diplomats criticized Haley for her lack of experience on the world stage since she has never held a position in the federal government. Democratic senators said she would get a "thorough" confirmation hearing, but that they would give her fair consideration.

US Trade Representative: Robert Lighthizer (confirmed)

Foto: source Skye Gould/Business Insider

Obama administration counterparts: Ron Kirk, Michael Froman

Duties: America's main trade negotiator, develop and recommend trade policy to the president, coordinate trade policy within the government

Reactions:Lighthizer lines up with Trump's stances on trade, particularly his harsh criticism of China, and even praised the businessman's trade policies in a 2011 op-ed in the Washington Times. Those who support free trade and disagree with Trump's views on the issue are therefore likely to disagree with Lighthizer, too. He does have experience serving in the executive branch, however - a characteristic many of Trump's Cabinet picks lack. Republican Sens. John McCain of Arizona and Ben Sasse of Nebraska voted against Lighthizer's confirmation because of his opposition to the "North American Free Trade Agreement's positive economic benefits."

Office of Management and Budget Director: Mick Mulvaney (confirmed)

Foto: source Skye Gould/Business Insider

Obama administration counterparts: Peter R. Orszag, Jacob J. Lew, Sylvia Mathews Burwell, Shaun Donovan

Duties: produce the president's budget, lead the Office of Management and Budget

Reactions: Mulvaney's desire to slash the federal budget is likely good news for Republican deficit hawks, but it clashes with Trump's plans to increase infrastructure and defense spending.

Environmental Protection Agency Administrator: Scott Pruitt (confirmed)

Foto: source Skye Gould/Business Insider

Obama administration counterparts: Lisa P. Jackson, Gina McCarthy

Duties: enforce US environmental laws like the Clean Air and Clean Water acts

Reactions: Environmental groups and Democratic leaders skewered the choice, citing Pruitt's climate change denial and his pending lawsuits against the EPA. Pruitt has described himself as a "leading advocate against the EPA's activist agenda," leading opponents of Trump's pick worried that he could dismantle the agency - and President Obama's environmental legacy in the process.

Small Business Administration Administrator: Linda McMahon (confirmed)

Foto: source Skye Gould/Business Insider

Obama administration counterparts: Karen Mills, Maria Contreras-Sweet

Duties: lead the Small Business Administration, which helps Americans start, grow and manage small businesses through policy initiatives, assistance, and loans

Reactions: Since McMahon built her and her husband's own small business into a massive empire, many are optimistic she will understand the needs of American small business owners.

Director of National Intelligence: Dan Coats (confirmed)

Foto: source Skye Gould/Business Insider

Obama administration counterparts: Dennis C. Blair, James R. Clapper

Duties: advise the president on national security, lead the 16-member US Intelligence Community, direct the National Intelligence Program

Reactions: Coats is well-respected among his fellow senators from both parties, and is expected to be confirmed easily.

CIA Director: Rep. Mike Pompeo (confirmed)

Foto: source Skye Gould/Business Insider

Obama administration counterparts: Leon Panetta, David Petraeus, John Brennan

Duty: oversee the Central Intelligence Agency

Reactions: Several Republican lawmakers praised Pompeo's directness, expressing confidence in his ability to lead the CIA. Pompeo has been criticized for anti-Muslim remarks he's made in the past - scrutiny that reemerged after Trump announced his appointment.

Chief of Staff: John Kelly

Foto: source Skye Gould/Business Insider

Obama administration counterparts: Rahm Emanuel, Pete Rouse, Bill Daley, Jack Lew, Denis McDonough

Duties: oversee the Executive Office of the President, serve as the president's right-hand man

Reactions: As the third retired general Trump has selected for a top leadership role, Kelly's choice has sparked fears among some experts that the incoming administration could have an imbalance between civilian and military relations. Those who oppose Trump's campaign promises likely won't agree with Kelly's support of the plan to build a wall on the border with Mexico or to keep the US military prison open in Guantanamo Bay, Cuba. But many applauded Trump's decision to move Kelly to the chief of staff role after Priebus was ousted in July, because the general imposes more order on the Oval Office.

National Security Adviser: Lt. Gen. H.R. McMaster (confirmed)

Foto: source Skye Gould/Business Insider

Obama administration counterparts: James Jones, Thomas Donilon, Susan Rice

Duties: Provide the president's daily national security briefing; coordinate the administration's foreign policy, intelligence, and military efforts

UPDATE 2/13: On February 13, Trump's first National Security Adviser, Lt. Gen. Michael Flynn, resigned after admitting that he may have discussed loosening American sanctions with Russia's ambassador to the US before Trump was sworn into office, despite previously insisting he hadn't. Flynn had been criticized for being anti-Islamic, for his questionable business ties to Turkey's increasingly authoritarian president, for what some saw as his overly positive views toward Russia, and for promoting conspiracy theories on Twitter during Trump's campaign. He was also accused of being too hawkish when he was DIA director, which is why a former Pentagon official alleged Flynn was forced out of the agency.

Reactions to McMaster: As a leading military scholar who's well-respected by his troops and known for pushing back on authority, McMaster is seen as a solid choice to replace Flynn, whose appointment was mired by controversy. Even Democrats praised the pick, calling McMaster "brilliant."

Counselor to the President: Kellyanne Conway

Foto: source Skye Gould/Business Insider

Obama administration counterparts: Valerie Jarrett, Brian Deese, Shailagh Murray

Duties: continue to act as one of Trump's most trusted senior advisers

Reactions: Some call Conway the "Trump Whisperer" for her ability to manage the president-elect and articulate his appeal to the public. Many expected Conway to take a role in Trump's administration since she has been such a close confidante managing his campaign, though she herself said she resisted taking the job since it could interfere with raising her children.

Other notable hires:

Foto: Gary Cohn, former COO and president of Goldman Sachs. source Reuters/ Ueslei Marcelino

Assistant to the President and White House Counsel: Donald F. McGahn

Deputy National Security Adviser: Kathleen Troia "KT" McFarland

Deputy Secretary of Commerce: Todd Ricketts

Administrator of the Centers for Medicare and Medicaid Services: Seema Verma

US ambassador to China: Iowa Gov. Terry Branstad

National Economic Council Director: Gary Cohn, COO and president of Goldman Sachs

National Security Council Chief of Staff and Executive Secretary: Lt. Gen. Keith Kellogg

National Security Council Senior Director of Strategic Communications: Monica Crowley

US Ambassador to Israel: David Friedman

(First two withdrew) Secretary of the Army: Vincent Viola, founder of Virtu Financial and owner of the Florida Panthers; Mark Green, Iraq War veteran and Republican state senator in Tennessee; Mark Esper, lobbyist for defense contractor Raytheon

Assistant to the President and Director of Trade and Industrial Policy on the National Trade Council: Peter Navarro, UC-Irvine economist

Special adviser to the president on regulatory reform: Carl Icahn, $16.7 billion hedge fund titan

Communications Director: Hope Hicks, Trump's spokesperson since the start of his presidential bid

Assistant to the President and Director of Social Media: Dan Scavino, also had the same role in Trump's campaign

Assistant to the President for Homeland Security and Counterterrorism: Thomas P. Bossert, was President George W. Bush's deputy Homeland Security Adviser

Special Representative for International Negotiations: Jason D. Greenblatt, Executive Vice President and Chief Legal Officer of The Trump Organization

Senior Adviser to the President: Jared Kushner, Trump's son-in-law

Assistant to the President: Ivanka Trump, the president's eldest daughter