William T. Coleman Jr., who championed the cause of civil rights in milestone cases before the Supreme Court and who rose above racial barriers himself as an influential lawyer and as a cabinet secretary, died on Friday at his home in Alexandria, Va. He was 96.

His death was confirmed by a spokeswoman for the international law firm O’Melveny & Myers, where Mr. Coleman was a senior partner in its Washington office. He lived at a care facility with his wife of more than 70 years, Lovida Coleman.

A lifelong Republican, Mr. Coleman was as comfortable in the boardrooms of powerful corporations — PepsiCo, IBM, Chase Manhattan Bank — as he was in the halls of government. He was the second African-American to serve in a White House cabinet, heading the Department of Transportation.

Mr. Coleman found success on the heels of a brilliant academic career, but he did so in the face of bigotry — what he called “the more subtle brand of Yankee racism” — from which his middle-class upbringing in Philadelphia did not shield him. In one episode, his high school disbanded its all-white swimming team rather than let him join it.