Coffey to Join Kramer Levin, in a Return to Practicing Law

John P. Coffey stood behind the lectern in a federal courthouse in Lower Manhattan this summer, firing off pointed questions and composing hand-drawn diagrams to defend his client, the former Goldman Sachs trader Fabrice Tourre.

Though Mr. Tourre lost the case, Mr. Coffey, who is known as Sean, caught the attention of the white-collar bar, and of one law firm in particular.

That firm, Kramer Levin Naftalis & Frankel, is expected to announce on Thursday that it has hired Mr. Coffey to be the chairman of its complex litigation group. The move, effective on Dec. 1, cements a return to active law practice for Mr. Coffey, a longtime litigator who recently worked at an investment firm.

“Getting up in court during the Fabrice Tourre trial brought home to me that that’s what I ought to be doing,” Mr. Coffey, 57, said in an interview. “I’m pleased to be going to a firm that not only has outstanding litigators but also folks who are not afraid to take a case to a jury.”

Mr. Coffey gained prominence as a plaintiffs’ lawyer at Bernstein Litowitz Berger & Grossmann, extracting $6.2 billion from big banks in the wake of WorldCom’s collapse. But he also has experience as a defense lawyer, and he will do both types of work at his new firm.

After an unsuccessful campaign for New York State attorney general and a stint as an investor in commercial lawsuits, Mr. Coffey returned to the legal spotlight in Mr. Tourre’s trial, working alongside Pamela Chepiga, a partner at Allen & Overy. Mr. Coffey, though, was not affiliated with a major firm, having created a solo law office for that case.

His new employer, a midsize firm that opened in 1968, is home to a number of prominent white-collar lawyers, including Gary P. Naftalis, who recently represented Rajat K. Gupta in an insider trading case. (Mr. Gupta, a former director of Goldman Sachs and Procter & Gamble, was found guilty last year of conspiracy and securities fraud.)

Mr. Coffey said he fielded calls from several law firms after the trial this summer, in which the Securities and Exchange Commission accused Mr. Tourre of misleading investors about a mortgage security that ultimately failed. In particular, Mr. Coffey won plaudits for his aggressive style in grilling the government’s witnesses.

“He had devastating cross-examinations. That is a skill that few people have,” said Barry H. Berke, a partner at Kramer Levin who is currently representing Michael S. Steinberg, a former portfolio manager at the hedge fund SAC Capital Advisors. “He’s going to light the bar on fire.”

Mr. Berke has observed Mr. Coffey as both an adversary and a colleague. In 1991, as a newly minted assistant United States attorney for the Southern District of New York, Mr. Coffey secured a guilty plea from a client of Mr. Berke in a narcotics case.

The two have crossed paths a number of times since then, with Mr. Berke serving as chairman of Mr. Coffey’s campaign for New York attorney general in 2010. They also worked together on President Obama’s campaigns in 2008 and 2012, manning his litigation “war room” in Chicago.

After losing his bid for attorney general, Mr. Coffey helped start BlackRobe Capital Partners, an investment firm that put money behind commercial lawsuits. At the time, he said he had no immediate plans to return to practicing law.

But after closing BlackRobe this year, Mr. Coffey was back in the courtroom. A graduate of the United States Naval Academy at Annapolis who once tracked Soviet submarines during the Cold War and was a personal military assistant to then-Vice President George H. W. Bush, Mr. Coffey said the experience brought back a familiar thrill.

“Getting ready for trial â€" it appeals to my warrior instinct,” Mr. Coffey said. “It was just a rush.”