Singer Paul Robeson, his son, Paul Jr., and daughter-in-law, Marilyn, chat with an unidentified woman under a portrait of Joseph Stalin at a Soviet Embassy party in Washington in 1951. Paul Robeson Jr. died April 26 at 86. (AP/AP)

During Paul Robeson Jr.’s childhood in the 1930s and ’40s, his father was one of the country’s first major African American stars. A onetime all-American football player who briefly practiced law, the senior Robeson appeared in movies, concerts and leading roles on Broadway.

He was also an outspoken advocate for social and racial equality and, in the 1930s, began to visit the Soviet Union. Between the ages of 9 and 11, Paul Jr. lived in Moscow, where he became fluent in Russian. He later trained as an electrical engineer, worked as a translator of ­Russian-language scientific journals and began to emulate his father’s activism.

In 1950, the senior Robeson’s U.S. passport was revoked when he refused to sign an affidavit that he was not a Communist — although he never joined the party. It was not restored for more than eight years, and the political ostracism severely damaged his career. He died in 1976.

The younger Mr. Robeson was, however, a member of the Communist Party for more than a decade, until the early 1960s. At a gathering at the Soviet Embassy in Washington in 1951, he and his father were photographed beneath a portrait of Joseph Stalin.

“I follow in my father’s cultural tradition,” he told the New York Times in 1993, “and like him, I am a black radical.”

Mr. Robeson Jr., who died April 26 at 86, devoted much of his life to protecting and preserving his father’s legacy and keeping alive his voice — both as a singer and as an activist.

Mr. Robeson Jr. released archival recordings of his father and wrote “The Undiscovered Paul Robeson,” a two-volume biography that received mixed reviews. He was a consultant on documentaries about his father’s life, including an “American Masters” film that premiered on PBS in 1999. He also directed a foundation that helped organize archives and other artifacts related to his father. (Some of the archives are housed at Howard University.)

In 1977, he led a high-profile campaign denouncing a new biographical play about his father by African American playwright Phillip Hayes Dean, who died April 14. More than 50 prominent black intellectuals, civil rights leaders and political figures, including Maya Angelou, Coretta Scott King and Rep. Charles Rangel (D-N.Y.) signed an open letter that ran as part of a two-page advertisement in Variety magazine.

They complained that Dean’s play, which featured James Earl Jones in the title role, did not adequately address Robeson’s political activism. Instead, they said it depicted him as a “naive, ignoble giant” and that African Americans “have repeatedly seen the giants among us reduced from revolutionary heroic dimensions to manageable sentimentalized size.”

Dean confronted Mr. Robeson and other signers of the open letter at a tense news conference in Washington in December 1977.

“I’m as black as anyone in this room,” the playwright said, defending his artistic freedom. “You have no right to say I am involved in some kind of a conspiracy to distort Paul Robeson.”

Dean’s play had a short run on Broadway in 1978 before having more successful revivals in 1988 and 1995. The protests died away, but Mr. Robeson never accepted the play’s depiction of his father.

“I still feel the character as written is a counterfeit,” he said in 1988.

Paul Robeson Jr. was born Nov. 2, 1927, in Brooklyn. An only child, he spent years in Europe before settling with his parents in Connecticut. He was a member of the football and track teams at Cornell University, where he received a bachelor’s degree in electrical engineering in 1949. He found it difficult to find work.

“I was unemployable because I was black and radical,” Mr. Robeson told the Los Angeles Times in 1993. “For years I used to record my father and do the sound for his concerts so he could hear himself on stage.”

Mr. Robeson, who lived in New York for many years, died in Jersey City of lymphoma, his wife, Marilyn Greenberg Robeson, said in a statement.

Besides his wife of 64 years, survivors include a daughter, Susan Robeson of New York; and a grandson. A son, David Paul Robeson, died in 1998.

In 1993, he published “Paul Robeson Jr. Speaks to America,” a book in which he argued that the country’s racial politics should be viewed as a mosaic of distinct ethnic identities instead of as a melting pot of many groups into one.

For years, however, he focused his most steadfast efforts on perpetuating the memory of his father.

“I would say the biggest thing about my father is that he was a genuine living hero, as distinct from a role model,” he said in 1993. “A hero in the sense that he dedicated his life to certain principles, to certain values, without fear of the consequences.”