Dick Sargent was born, Richard Cox, on April 19, 1930 in Carmel, California. His mother, Ruth McNaughton, was the daughter of Los Angeles' Union Stockyard baron John McNaughton. Billing herself as Ruth Powell, she appeared in a handful of silent films, including Rex Ingram's Four Horsemen of the Apocalypse (1921). Sargent's father, Colonel Elmer Cox, was a war hero and entrepreneur whose many jobs including acting as business manager for director/actor Erich Von Stroheim and actor Douglas Fairbanks.

Richard attended the San Rafael Military Academy and the Menlo School in California. He concluded his academic career at Stanford University, where he studied acting and performed many plays getting a taste for live theatre. By the time he graduated, he had appeared in 25 campus productions. After college, Dick, as he chose to be called, pursued his acting career and held many odd jobs, one of which was digging ditches. Sargent had a tough start to his acting career and tried many odd jobs to make ends meet. Leaving a position as a department store salesman, he journeyed to the colonial city of San Miguel Allende in Mexico to enter the import-export business.

He carried his love of Mexican art and culture with him when he went back to California. When he returned, he made the transition from live theatre to feature films and later television. When he won a bit part in 1954's Prisoner of War (with Ronald Reagan), Dick changed his last name from Cox to Sargent (not Sergeant). His first major role in a motion picture was as P. F. Wilson in 1957's Bernadine, for which he received a Laurel Award from the nation's film exhibitors. He shared the screen with Cary Grant in Operation Petticoat (1959) and That Touch of Mink (1962). His other movies included The Great Imposter (1961), Captain Newman, MD. (1963), For Love or Money (1964), The Ghost and Mr. Chicken (1966) and Elvis Presley’s Live a Little, Love a Little (1968).

Though he did well enough in small supporting film roles, his career didn't take off until he entered television. Before starring on Bewitched, Sargent was in several other shows. He made appearances in such shows as Gunsmoke, Wagon Train, I Dream of Jeannie, and Adam-12. He played a lead role in One Happy Family (1961) and Broadside (1964).

Sargent and Tammy Grimes were said to have successfully auditioned for the original roles of Darrin and Samantha Stephens during the initial casting of the pilot episode of Bewitched. Sargent became unavailable because he was under contract to Universal for a TV show called Broadside. Later, Sargent went on to play Tammy Grimes's brother on her short lived series The Tammy Grimes Show, where the lead character's name was Tamantha. Grimes was also under contract and unable to play the part of Samantha. Sol Saks, the creator of Bewitched, was such a fan of the elf-like Tammy Grimes that he was willing to wait a year for her to be free from her pending contract. However, ABC was not. When Bill Asher and Elizabeth Montgomery were approached about the series, the production schedule was escalated and Dick York was cast as Darrin.

By the time health problems forced Dick York (the original Darrin Stephens) to leave the series in 1969, Sargent was no longer committed to Universal, so he was finally able to take the part. Sargent was welcomed into the cast, but did not have an easy time stepping into this top show. He often appeared nervous and uncomfortable in his first season. Because the show had been running for so long, scripts began being recycled with Sargent performing the same dialogue that York had previously done. There was a major difference in the reactions of the two "Darrins" to the outlandish situations put upon them by Samantha and her witchly relatives. On the plus side, replacing Darrin provided fans of the show three additional colour seasons of Bewitched.

After Bewitched, Dick Sargent went on to guest star in many popular sitcoms throughout the 70s and 80s. The list includes such TV classics as Taxi, Alice, Charlie's Angel (he played Hugh in the cult classic "Angels on Wheels" episode), Diff'rent Strokes, Fantasy Island, The Dukes of Hazzard, The Waltons, The Love Boat, Three's Company, Family Ties, The Six Million Dollar Man, Murder, She Wrote, and L.A. Law. Sargent had dramatic roles in TV movies after Bewitched, in Melvin Purvis: G-Man (1974), Rich Man, Poor Man (1976), The Gossip Columnist (1979), The Power Within (1980), and Columbo: Uneasy Lies the Crown (1990).

Sargent also went back to feature films, most of which went straight to video. He starred in Parts: The Clonus Horror (1978), Hardcore (1979), Body Count (1987), Murder by Numbers (1990), Twenty Dollar Star (1991), Frame Up (1991), and his final role as Mr. Randolph in 1993's Acting on Impulse. In all, Sargent appeared in twenty-three motion pictures, four made-for-TV movies, and five series of his own. He also did voice work for commercials and went back to performing live theatre when he had the chance.

In 1989. Sargent was diagnosed with prostate cancer. Knowing that he was ill, Sargent became what he called a "retroactive role model" for the gay and lesbian community. After keeping his personal life out of the media's scrutiny throughout a long-standing and successful acting career, Sargent publicly came out in 1991 after an article ran in a tabloid. He found the article to be seedy and inaccurate, and wanted to set the record straight. Sargent's ABC press biography and the few interviews he had done during his years as Darrin Stephens had manufactured an ex-wife to avoid speculation about his sexuality. Sargent was never married, but had a long-time companion whom he was with for 20 years before the man's death in 1979.

Sargent personally felt great relief in finally being open about his lifestyle, and professionally felt that he was doing a great service to other homosexuals who could gain the courage to come out to their friends and family. Sargent, like Dick York, was dedicated to ridding the world of hunger and offered hope and support in places where there was little of either. He had been a life-long advocate of the Special Olympics, and now he used his position to advocate for gay rights.

Despite radiation therapy and regular treatment for his cancer, Sargent passed away on July 8, 1994 at the age of 64.