Born Pamela Ostrer in Westgate-on-Sea, Mason was the daughter of Isadore, a mill owner, and Helen Ostrer. She left school at age 9 and age 16, married Roy Kellino. She began acting in 1934, and in 1939 she and Kellino made their first film together I Met a Murderer (1939). After divorcing Kellino in 1940, she married actor James Mason with whom she had two children. She remained married to him until 1964.
Mason went on to appear in various films including Lady Possessed (1952), The Child (1954), Sex Kittens Go to College (1960), and The Sandpiper. She also guest starred on Schlitz Playhouse of Stars, Playhouse 90, Love, American Style, and The New Dick Van Dyke Show.
She also hosted two talk shows The Pamela Mason Show from 1965-1966, and The Weaker (?) Sex from 1968-1969. In addition to acting, Mason authored several books including Marriage Is the First Step Toward Divorce and The Female Pleasure Hunt,