Mr. Andres, 52, is among several members of the Mueller team who came from private practice, and he is believed to be the first to return.

Most of the lawyers were temporarily assigned to the inquiry from other posts in the Justice Department and many are returning to United States attorneys’ offices and other department jobs; at least one other prosecutor is going into private practice . One will teach at a law school.

At Davis Polk, where Mr. Andres was a partner before joining the special counsel’s team in August 2017, he will return to handle white-collar defense and other litigation. During his time in Washington, he lived in a sparsely furnished one-bedroom apartment near Union Station, a short walk from the Special Counsel’s office and a location that would hasten his Amtrak commute home to New York on weekends to see his wife — a federal judge — and their three daughters. Mr. Andres said he is happy “to be home.”

Earlier in his career, Mr. Andres spent a dozen years at the Justice Department, 10 of them as a prosecutor at the office of the United States attorney’s office for the Eastern District of New York in Brooklyn. There, he eventually rose to head the office’s Criminal Division.

He had handled scores of cases against organized crime figures, playing a central role in an effort that gutted the Bonanno crime family and led to the convictions of more than 70 mobsters. He led the team that won murder and racketeering convictions against the Bonanno boss, Joseph C. Massino, who in 2005, facing the death penalty, became the first Mafia chieftain to testify against his own family.

Mr. Massino revealed at the time that Mr. Andres’ success against the Bonannos had not gone unnoticed. He told the F.B.I. that the family’s then acting boss, Vincent Basciano, known as Vinny Gorgeous, had plotted to kill Mr. Andres and the federal judge who oversaw Mr. Basciano’s trial.

Mr. Andres spent his final two years at the Justice Department in Washington, working as a deputy assistant attorney general, overseeing the Criminal Division’s sections for fraud, organized crime and gangs, death penalty cases and appeals. He helped oversee some of the earliest efforts to prosecute crimes arising from the 2008 financial crisis.

Now, he will be defending some of the same types of companies and executives.

“No one is really better at getting to the heart of complex financial issues, and that includes convincing the government when it doesn’t have a case,” said Neil MacBride, the former United States attorney in the Eastern District of Virginia who is now the co-head of Davis Polk’s white-collar defense group.

Noah Weiland contributed reporting.