Christine Riley was born in Amityville, Long Island, New York to Joseph J. Riley and Mary Belford Riley (née Wilson; later Malone), who later divorced. She has a brother, Terry, and a sister, Shawn. The family once lived at 112 Ocean Avenue, the location which later became famous as the setting of The Amityville Horror, for about five years from age 11 until age 16. As a young child and teenager on Long Island, she was active in Equestrian trials, winning many horsemanship awards. "She was enrolled at the best schools and joined the best swimming and yachting clubs on Long Island." After graduating from high school in 1966, she attended Hofstra University, initially interested in a career in psychiatry. However, the classwork she did with Joseph Leon, the head of the drama department there, inspired her to become an Actress.

She appeared in guest roles on many popular television shows of the 1970s, 1980s, and 1990s, including Ironside, Banacek, Mannix, Barnaby Jones, Owen Marshall: Counselor at Law, The Six Million Dollar Man, Wonder Woman, Magnum, P.I., Hart to Hart, The Incredible Hulk, Family Ties, The Golden Girls, Blossom, Beverly Hills 90210 , Battlestar Galactica (specifically as one of the prison-barge inmates recruited to destroy "The Gun On Ice Planet Zero"), The Paper Chase: The Television Series, My Two Dads Night Court (specifically the 1992 episode "Opportunity Knock Knocks," where she was credited as Christina Belford), Murder, She Wrote, and Diagnosis: Murder.

Her first appearance on television was as an extra on the Vince Edwards series Matt Lincoln. Her first credited appearance on television was in the NBC television movie Vanished in 1971. She played insurance investigator Carlie Kirkland during the second season (1973–74) of Banacek. She appeared in the 1980 TV-movie The Gambler with Kenny Rogers and also played the mother on Silver Spoons and Jackie on Empire.

Belford's feature-length films include the Paul Newman film Pocket Money (1972), the George Peppard film The Groundstar Conspiracy (1972), the horror film Christine (1983), and the straight-to-video 1986 film The Ladies Club.

She appeared in the episode "Devil Pack" from the 1977 series Quinn Martin's Tales of the Unexpected (known in the United Kingdom as Twist in the Tale), as well as in various television films through the years. Her last appearance on television was in the horse-racing TV movie Ruffian, starring Sam Shepard and broadcast on the ABC network in 2007.

She played on Dynasty as the nurse for Fallon's baby at the end of Season 2 and Season 3. In 1983, she co-hosted, in Los Angeles, with Steve Edwards, Cathy Kronkite, and Ruth Batchelor, an unsuccessful pilot for a daytime-magazine series, Personal & Confidential, over five days (August 1–5, 1983).

From the 1990s to the present, Belford has done much voiceover work, including commercials, animations, promotional spots, and narrations.

Belford has been married to actor Nicholas Pryor since July 1993.