Peter M. Fishbein, a prominent litigator who helped build the New York law firm Kaye Scholer into a national powerhouse, represented the disgraced savings-and-loan mogul Charles H. Keating Jr., and was sued by the government and accused of concealing his client’s corruption, died on Sept. 25 at his home in Harrison, NY. He was 91.

Mr. Fishbein, a partner at Kaye Scholer since 1967, was regarded as a lawyer of broad talents. He worked on mergers and acquisition, First Amendment cases and criminal defense. He argued before the Supreme Court on behalf of Texaco and represented the maverick investor Herbert J. Siegel, who became a billionaire after helping to clear the way for Warner Communications to merge with Time Inc. in 1989. He took leaves of absence from his law firm to work on former U.S. Attorney General Robert F. Kennedy’s successful 1964 U.S. Senate race in New York and on Mr. Kennedy’s 1968 presidential campaign.