"I offered to resign last night and President Trump said, 'Let's talk about it tomorrow,' " Bolton tweeted about 10 minutes after Trump's announcement.
As is typical under Trump, the firing unfolded on Twitter and Fox News in dramatic fashion. Bolton, from the White House, texted Fox News host Brian Kilmeade while he was on the air.
"John Bolton just texted me, just now, he's watching," Kilmeade said on the air. "He said, 'Let's be clear, I resigned.' "
Less than an hour earlier, the White House had notified reporters that Bolton would appear at a 1:30 p.m. briefing with two Cabinet officials.
Trump's announcement came as a surprise, even though Bolton's increasing isolation from Trump and lack of influence on foreign policy matters was no secret within the White House. Bolton pushed back on several of the president's major initiatives, and the two often clashed when formulating policy. Trump had promised to reduce involvement in foreign conflicts, and he viewed Bolton as too eager to advocate military force.
After Trump canceled his proposed meeting last weekend at Camp David with members of the Taliban and the Afghan government, stories quickly emerged that Bolton had strongly opposed the summit and the proposed peace deal with the Taliban -- and to some at the White House, he appeared to take credit for their collapse.
According to a senior administration official, Trump came to believe that Bolton "was not fully on the team" as he balked at defending Trump publicly and as forcefully as Secretary of State Michael Pompeo and Vice President Mike Pence have.
Trump, the official said, believed Bolton and his staff leaked stories about internal division, including those related to the president's scuttled meeting with the Taliban last weekend. Pence ardently pushed back on that narrative in a tweet, and Pompeo took to the airwaves Sunday, appearing on all five morning politics shows to defend and explain the president's decisions.
Bolton, who had canceled several recent television appearances, did not offer the same sort of public defense or praise for the president.
Bolton, a prominent hawk, was appointed in April 2018 -- also announced by presidential tweet, surprising Bolton at the time. During his 17 months in the job, he advocated aggressive stances toward Iran, North Korea and Afghanistan that at times put him in conflict with the president.