Remembered for his work in Western movies and television series, he is perhaps most well known for his portrayal of Marshal Micah Torrance on the ABC series The Rifleman. His other credits include the TV series The Virginian, Gunsmoke, and Wagon Train and the films Ride Beyond Vengeance, Young Billy Young and Wanda Nevada.
After serving in the United States Army during the World War I years, he made his first credited cinematic appearance in the 1926 feature Hoodoo Ranch.
He played the judge in the classic 1962 film To Kill a Mockingbird.
The son of German-born parents Louise and Wilhelm Fix, he spent his youth in Dobbs Ferry, New York. His marriage to Frances Harvey produced a daughter named Marilyn, who later married actor Harry Carey, Jr. Fix's second marriage -- to Beverly Pratt -- lasted from 1949 until Pratt's death in 1979.
He played the father of Elizabeth Taylor's character in the 1956 film Giant.