Whitman Blount Mayo was born in New York City, New York, and grew up in Harlem and Queens. At the age of seventeen he moved with his family to Southern California and from there entered the United States Army, serving from 1951 to 1953 during the Korean War. Upon release, he studied at Chaffey College, Los Angeles City College, and UCLA. During this time he began acting in small parts, while waiting tables, working in the vineyards and as a probation officer as well as a variety of other small jobs. He also spent seven years as a counselor to delinquent boys. In the early 1970s, while working for the New Lafayette Theatre, Norman Lear offered Mayo a role as Grady Wilson on Sanford and Son. The character’s name was based on Grady Demond Wilson, the actor who played Lamont Sanford. During a period where Redd Foxx did not appear on the show due to a contract dispute, Grady moved into the Sanford house and effectively starred in the show for four episodes. Mayo would later star in Grady, an unsuccessful spin-off in which his character moved in with his daughter and her husband in Beverly Hills. After its cancellation in 1976, Mayo’s Grady character returned to Sanford and Son.

Mayo reprised the role in the unsuccessful 1977 NBC-TV spinoff series Sanford Arms opposite actor Theodore Wilson, as well as for two episodes of Sanford, another NBC-TV Sanford and Son spinoff, this time opposite Redd Foxx and actor Dennis Burkley, in 1981. Also in the late 1970s, Mayo appeared on the Los Angeles children’s television program That’s Cat, offering sage advice in a sweet manner to the main character, Alice. In 1991 he appeared in an episode of Full House called “The Volunteer”. He played a senior named Eddie Johnson. In 1996, Late Night with Conan O’Brien spent several weeks trying to have Mayo appear on the show. The show aired a mock episode of Unsolved Mysteries. On February 8, 1996, Mayo appeared on Late Night, to much fanfare. Mayo also played a role in The Cape as Sweets, the owner of Moonshot Bar and Grill. Mayo made several film appearances, including The Main Event with Barbra Streisand, D.C. Cab, Boyz n the Hood and Waterproof with Burt Reynolds. Mayo also appeared as Reverend Banyon on the BET TV Movie Boycott in 2001 and in an episode of Martin. He hosted Liars and Legends on Turner South. Mayo taught drama at Clark Atlanta University. He opened a travel agency in Inglewood, California. Mayo died of a heart attack at Atlanta’s Grady Memorial Hospital. He had resided in Atlanta’s Historic Collier Heights community since 1994 and was survived by his third wife, Gail Mayo. His son, Rahn Mayo, became a member of the Georgia House of Representatives in 2009.