Conrad Stafford Bain was born on February 4, 1923, in Lethbridge, Alberta, Canada, as a twin son to Stafford Harrison Bain and Jean Agnes (née Young). He developed an interest in acting while in high school and trained at the Banff School of Fine Arts, where he met his future wife Monica Marjorie Sloan.
Conrad's acting pursuit was interrupted by World War II, during which he joined the Canadian army. After his discharge, he studied at the American Academy of Dramatic Arts in New York and married Monica in 1945. The couple had three children, Jennifer, Mark, and Kent.
Conrad made his stage debut in a Connecticut production of "Dear Ruth" in 1947 and went on to appear in various stage productions, including "Jack and the Beanstalk" and "The Barretts of Wimpole Street". He made his off-Broadway debut in a 1956 revival of Eugene O'Neill's "The Iceman Cometh", which starred Jason Robards.
Conrad's breakthrough role came when he was cast as Arthur Harmon, the conservative doctor and husband of Rue McClanahan's character Maude Finlay, in the popular sitcom "Maude" (1972-1978). He then starred as Phillip Drummond, the wealthy father of a girl and adoptive father of two African-American children, in the sitcom "Diff'rent Strokes" (1978-1986).
After "Diff'rent Strokes", Conrad appeared in a third sitcom, "Mr. President" (1987),and continued to work in television and stage productions throughout the 1990s and early 2000s. His last on-camera appearance was a 1996 episode of "The Fresh Prince of Bel-Air", in which he reprised his role as Phillip Drummond.
Conrad Bain passed away on January 14, 2013, at the age of 89, in a retirement home in Livermore, California.