The tweet came as Sims was in the middle of his latest interview, this one on CNN.
“Nice,” Sims said when the tweet was read on the air. “There it is.”
Sims said he knew that being on the receiving end of an angry Trump tweet was a possibility when he wrote his book, “Team of Vipers,” which includes a mix of praise and criticism for a president he served for 500 days in the White House.
“My identify is not wrapped up in being a Trump staffer,” Sims said. “My identity is wrapped up in who I am in my faith. Those are things that matter to me. I know who Jesus says I am. It don’t matter to me what Donald Trump or anyone else says that I am.”
Shortly after the appearance, Michael Glassner, the chief operating officer of the Trump campaign, announced via Twitter that the campaign is preparing to sue Sims, whom it accuses of violating a nondisclosure agreement.
The campaign and the White House have made a regular practice of requiring employees to sign agreements aimed at preventing them from saying disparaging things about Trump.
Similar threats have been made in the past, sometimes without follow-through.
During the CNN interview, Sims, who worked on the Trump campaign before joining the White House, said he wasn’t sure whether he had signed such an agreement.
Sims had frequent access to Trump early in the administration, often attending meetings. But his access was curbed after John Kelly became chief of staff, according to current and former administration officials, who spoke on the condition of anonymity to describe internal White House dynamics.
Sims was caught near the end of his tenure surreptitiously recording the president, these officials said.
A number of aides encouraged the president not to tweet about Sims’s book this week, arguing that would give it further publicity, the officials said. But Trump grew frustrated with the television appearances.
“The video guy?” Trump asked incredulously last week, when told about the book, according to two senior administration officials. Sims often filmed the president delivering his weekly address to the nation.
Sims is not the first former staff member whom Trump has sought to diminish following publication of a tell-all book.
In August, he called former White House aide Omarosa Manigault Newman “a crazed, crying lowlife” and “that dog” in a tweet as she was making publicity appearances for her book, “Unhinged.”
Unlike the memoirs of other Trump officials, Sims’s book is neither a sycophantic portrayal of the president nor a blistering account written to settle scores.
Sims presents himself as a believer in Trump and his agenda but is still critical of him, especially regarding moral issues. Sims also finds fault in himself, writing that he was sometimes “selfish,” “nakedly ambitious” and “a coward.”
Philip Rucker contributed to this report.