American actor drafted for the military after his debut picture, “Since You Went Away,” 1944. Signing a postwar contract with Columbia, he was named “most popular find” of 1949. His films include “All the King’s Men” and “Rogues of Sherwood Forest.”
Derek was the son of theatrical parents who separated when he was five. Cameraman Russell Harlan became John’s father figure; he taught the boy to ride and swim, but it was his mother whom he adored and protected. Even when he spent time visiting with his dad, he would visit his mom every day after school and he later admitted to being terribly spoiled. His coaching began when he was 17, under contract to Selznick, but he seldom turned up for classes.
Derek spent 1945-1946 in the army as a paratrooper, making 16 jumps. Post-war, he signed with Columbia in 1949 and was cast in “Knock on Any Door.” The fan magazines labeled him a star before the film was even released, labeling it his debut even though he had played small roles in “Since You Went Away” and “I’ll Be Seeing You” in 1944. When the movie came out, the studio was flooded with fan mail from both young men and women, the biggest deluge in history.
All that Derek was interested in at the time was girls, horseback riding and cars. His only interest in acting was as a source of income, and he coasted through a series of action and adventure pictures in costume.
A handsome man, he married gorgeous women who also had reputations of being nice people, with whom he managed to establish deep friendships after the marriages concluded. He was married to Patti Behrs, 1950-1955; two kids. In 1957 he married Ursula Andress. From 1965 to 1975 he and Linda Evans were wed. Derek met 16-year old Bo Shane when he was 46; they married in 1977. His distaste for glamour notwithstanding, their home was complete with waterfall, fur rugs and animal-hide tabletops, along with an Excalibur automobile.
Doubling over with pain in October 1997, Derek was diagnosed with having kidney stones. His doctors blasted the stones with ultrasonic sound waves and Bo literally forced him to drink gallons of water a day for seven weeks. He was found unconscious at his ranch in Santa Inez Valley, California and died on 22 May 1998 during emergency heart surgery in the hospital in Santa Maria, California, his wife Bo was at his side.
Link to Wikipedia biography