She appeared under the stage name of "Ruth Powell", and had supporting bit roles in such films as The Four Horsemen of the Apocalypse and Hearts and Trumps with Alla Nazimova.

Sargent's father Elmer served in World War I and later became a business manager to Hollywood figures, including Douglas Fairbanks and Erich von Stroheim.

He was a regular in three short-lived television comedies, One Happy Family in 1961, Broadside in 1964,[2][3] and The Tammy Grimes Show, a four-episode ABC flop in 1966.

For three seasons, from 1969 to 1972, he played Darrin Stephens — a role he had previously turned down[citation needed] — in Bewitched, replacing ailing actor Dick York.

He played Harry in Live a Little, Love a Little (1968) opposite Elvis Presley and Michele Carey, and made guest appearances on television series, including Navy Log, The West Point Story, Medic, Code 3, Ripcord, Gunsmoke, Wagon Train, The Alaskans, The Adventures of Ozzie and Harriet, The Rat Patrol, I Dream of Jeannie, Hazel, Dr. Kildare, Daniel Boone, Kraft Mystery Theater, Three's Company, The Waltons, Charlie's Angels, Knots Landing, Family Ties, The Love Boat, Fantasy Island, Adam-12, The Streets of San Francisco, Owen Marshall: Counselor at Law, Ellery Queen, The Tony Randall Show, The Devlin Connection, Baretta, Switch, The Six Million Dollar Man, Marcus Welby, M.D., Trapper John, M.D., Matt Houston, Alice, Taxi, Benson, Vega$, Diff'rent Strokes, Here's Lucy, Love, American Style, The Yellow Rose, The Commish, Finder of Lost Loves, Murder, She Wrote, L.A. Law and Harry and the Hendersons.

[5] The high rate of suicide among young gay people was the main reason; he jokingly referred to himself as a "retroactive role model".

Former Bewitched co-star Elizabeth Montgomery commented, "He was a great friend, and I will miss his love, his sense of humor and his remarkable courage.