A veteran of the bureau, Mr. Abbate has served as deputy director since early 2021 and took the helm from Christopher A. Wray as the agency faces an uncertain future.
The F.B.I.’s acting director retired on Monday as the bureau faces a potentially tumultuous leadership change under the Trump administration.
The acting director, Paul Abbate, took command of the bureau on Sunday after the departure of Christopher A. Wray, the previous director who decided last month to step down before the inauguration. President-elect Donald J. Trump appointed Mr. Wray in 2017 but publicly attacked him and the F.B.I., which had repeatedly investigated him.
In a rare move before leaving the bureau, Mr. Wray extended the service of Mr. Abbate, who is 57, the mandatory retirement age of F.B.I. agents.
Mr. Abbate was named deputy director in February 2021, and Mr. Wray has said it was one of the best decisions he made during his time at the bureau. As deputy, Mr. Abbate oversaw all of the F.B.I.’s domestic and international investigative and intelligence activities and operations. The bureau has about 38,000 employees with agents stationed around the world and other U.S. agencies.
Mr. Trump has said he will nominate Kash Patel, 44, to be the bureau’s next director, but his confirmation hearing has not been scheduled yet. Typically the acting director would remain in place until Mr. Patel was confirmed by the Senate to ensure stability at the highest ranks of the bureau.
Mr. Patel worked as a prosecutor at the Justice Department’s national security division from 2014 to 2017 and is expected to face bruising questions about his qualifications. He lacks the experience of previous directors, but his unwavering loyalty to Mr. Trump has catapulted him to consideration for the F.B.I.’s top job.