- Attorney General Jeff Sessions -
Sessions, a Republican senator from Alabama, was the first member of the Senate to back Trump's insurgent bid in 2015 for the Republican presidential nomination.
After winning the presidency, Trump rewarded Sessions by naming him to head the Department of Justice.
But relations between the two quickly soured after Sessions recused himself from Special Counsel Robert Mueller's probe into whether the Trump presidential campaign colluded with Russia to get him elected.
Trump personally attacked Sessions on several occasions for failing to protect him from the Mueller probe.
"I don't have an attorney general," Trump told Hill.TV in an interview in September. "It's very sad."
- UN Ambassador Nikki Haley -
Haley, who announced in October that she would leave the administration at the end of 2018, was a shining star of the administration from the start.
Thrust onto the international stage, she quickly became an astute advocate for Trump's foreign policy, using forceful language against North Korea, Syria and Iran.
The former South Carolina governor was also unafraid to speak her mind, often in fairly undiplomatic language, and built a reputation for standing up to Trump when she felt it was warranted.
Her aggressive criticism of Russia won plaudits, even as she stepped beyond the position held by the White House.
Her resignation announcement last month sparked speculation about her political future, though she denied any plans to challenge Trump in 2020, saying she would remain loyal to the president.
- Environment chief Scott Pruitt -
Environmental Protection Agency head Scott Pruitt's tenure was beset by scandal, and Trump pushed him out in July.
A former Oklahoma attorney general with ties to fossil fuel industries, Pruitt was accused of using his position to enrich his family's lifestyle in violation of federal law.
- Secretary of State Rex Tillerson -
Rex Tillerson was fired by Trump in March, ending a rocky tenure for the former Exxon chief executive as the nation's top diplomat.
Tillerson was frequently at odds with the mercurial president. They notably disagreed on the Iran nuclear deal, from which Trump withdrew in May.
During his brief stay at Foggy Bottom, Tillerson frequently found himself out of the loop and caught unawares by policy shifts announced in Trump tweets.
In one of his first public criticisms of the president since stepping down, Tillerson told a gathering in Texas earlier this month that Trump was undisciplined, did not like to read briefing papers and sometimes asked him to do things that were illegal.
Trump shot back on Twitter that Tillerson was "dumb as a rock."
- Chief strategist Steve Bannon -
The architect of Trump's nationalist-populist campaign and his election victory, White House chief strategist Steve Bannon was nicknamed the Prince of Darkness and the Shadow President.
His economic nationalism became the lynchpin of Trump policies, even as many of Bannon's other ideas were rebuffed by policy rivals.
Bannon's constant clashes with other advisors became untenable, as did his ties to the extreme right. Bannon left in August 2017.
- National Security Advisors Flynn, McMaster -
Michael Flynn, a retired lieutenant general, was being investigated for his contacts with Russians and eventually pleaded guilty to lying to the FBI.
He lasted only 22 days as national security advisor.
Flynn's replacement, HR McMaster, also a lieutenant general, lasted barely a year.
He never really clicked with the president, who bristled at McMaster echoing the US intelligence establishment consensus that Russia meddled in the 2016 election.
