Al Mulock was the great-grandson of Sir william Mulock (1843–1944), the former Canadian Postmaster-General. He was married to Actress Steffi Henderson, but she died in 1967 of cervical cancer. They had one child, Robin Mulock, who now goes under the name of Marcy Eclipse Neilson and lives in Rhode Island, United States.

Alfred Mulock Rogers was born on 30 June 1926 in Toronto, Ontario, Canada. He was the only child of Adèle Cawthra Mulock (1904–1970) and Alfred Rogers. Maternally he was descended from the Mulock family, headed by Sir william Mulock KCMG, the former Postmaster-General of Canada and one of the wealthiest families in the then-Dominion of Canada.

He attended the Lee Strasberg's Actors Studio in New York City, United States. Then, with David de Keyser, he started The London Studio, which taught method acting to British actors. Mulock became active in the British film industry in the 1950s and early 1960s, making numerous appearances in various British television series and films.

Mulock committed suicide by jumping from his hotel room in Guadix, Granada, Spain in May 1968, while filming for Once Upon a Time in the West. He was wearing his cowboy-style costume at the time of his fall. Mickey Knox, Screenwriter for the film, and production manager Claudio Mancini witnessed Mulock's suicide as his body passed their hotel window near the end of the shoot. Mulock survived the fall, but suffered a pierced lung from a broken rib during the bumpy ride to the hospital. Before being taken away in the ambulance, Director Sergio Leone shouted, "Get the costume, we need the costume."