Roger Wilkins, who championed civil rights for black Americans for five decades as an official in the Kennedy and Johnson administrations, a foundation executive, a journalist, an author and a university professor, died on Sunday in Kensington, Md. He was 85.

His daughter Elizabeth confirmed his death, at a care facility. The cause was complications of dementia.

A black lawyer in the corridors of power, Mr. Wilkins was an assistant United States attorney general, ran domestic programs for the Ford Foundation, wrote editorials for The Washington Post and The New York Times, taught history at George Mason University for nearly 20 years and was close to leading lights of literature, music, politics, journalism and civil rights. Roy Wilkins, who led the N.A.A.C.P. from 1955 to 1977, was his uncle.

Roger Wilkins’s early mentor was Thurgood Marshall, the renowned civil rights lawyer who became the Supreme Court’s first black associate justice. And he organized Nelson Mandela’s triumphant eight-city visit to the United States in 1990 as millions turned out to see that living symbol of resistance to apartheid after his release from 27 years in prison in South Africa.

Beyond attending a segregated elementary school as a boy and being arrested once in a protest against apartheid, Mr. Wilkins had little personal experience with discrimination. He waged war against racism from above the barricades — with political influence, jawboning, court injunctions, philanthropic grants, legislative proposals, and commentaries on radio and television and in newspapers, magazines and books.

Outwardly, he was a successful, popular black man with more white acquaintances than black friends. The second of his three wives was white.

A lean, intense, soft-spoken intellectual, he grew up in a genteel middle-class family. The customs, attitudes and social currencies of everyday black life “evolved away from me,” he said in a memoir.

“I didn’t know how to talk, to banter, to move my body,” he said.

It mattered. As he rose to prominence, he came to regard himself as a token black in institutions and social circles that were overwhelmingly white and privileged. It troubled him deeply. In the memoir, “A Man’s Life: An Autobiography” (1982), he cited struggles with depression, suicidal thoughts and drinking problems, and acknowledged years of unease with his blackness, of trying to live up to the expectations of whites.

“Instead of standing with my nose pressed to the window, I often found myself inside rooms with people whose names were Mailer, Vidal, Javits, Kennedy or Bernstein,” he wrote. He was surrounded at work by middle-aged white men, while “my night world was virtually lily-white,” he added. “It was as if, by entering that world at night, I was betraying everything I told myself I stood for during the day.”

A University of Michigan law school graduate, Mr. Wilkins went to Washington on a wave of New Frontier fervor in 1962 to join the Kennedy administration. He became special assistant to the head of the Agency for International Development. He was soon spotted as a savvy, if outspoken, Democratic asset, and joined campaigns for passage of the Civil Rights Act of 1964 and the Voting Rights Act of 1965.

In 1965, President Lyndon B. Johnson named him the administration’s chief troubleshooter on urban racial issues. He became an assistant attorney general, ostensibly to calm the unrest racking cities. He spoke dutifully against violence and met mayors and community leaders, but…