Grant Williams. Best known for his first-rate performance in the sci fi classic The Incredible Shrinking Man (1957), Williams seemed to be on the cusp of stardom in the 1950s. He signed with Warner Bros. in 1960 and became relegated to supporting roles in films like Susan Slade (he played Susan's mountain-climbing lover Conn White). Even worse, he was cast in the 1959-63 TV series Hawaiian Eye midway through its run. The overexposure did not help his screen career; his last major film role was in PT 109, in which he was listed fifth in the cast. Through the rest of the 1960s, he guest starred in TV series such as Perry Mason and Bonanza. His last screen appearance was in the low-budget sci fi film Brain of Blood. Williams, who had studied acting with Lee Strasberg, subsequently opened a drama school. He died at age 53 of peritonitis, an inflammation of the abdomen wall.
Gardner McKay. After a short stint in a TV Western called Boots and Saddles, Gardner McKay was cast in Adventures in Paradise, a 1959-62 television series based on the works of James A Michener. He became an instant TV heartthrob and was sought after for film roles when the series ended. He turned down a chance to star opposite Marilyn Monroe in Something's Got to Give. Indeed, post-Paradise, McKay appeared in only two movies before retiring from acting. One of those films was The Pleasure Seekers, a pleasant remake of Three Coins in the Fountain, which highlighted his easygoing charm. McKay became a sculptor, novelist, and playwright. His art work has been displayed at the Museum of Modern Art and he won the L.A. Drama Critics' Circle Award for his play Sea Marks. He died of prostate cancer at age 69.
John Dall. He earned an Oscar nomination opposite Bette Davis for The Corn Is Green, had a major role in Hitchcock's Rope, and starred in a famous cult film (Gun Crazy). And yet, John Dall never achieved stardom and, in fact, appeared in only eight films during a 15-year acting career. That would lead one to assume that he focused on a stage career, but he only appeared in four Broadway plays. His biggest stage success was in Dear Ruth. He played the role of Lieutenant William Seawright in the original 1944 production for 680 performances--only to see the 1947 film role go to William Holden.
George Maharis. For those that question the handsome Maharis' acting ability, I recommend that you watch the first two seasons of Route 66. Maharis had the best role of his career as the street-smart, passionate Buz Murdock and shined in episodes like "Birdcage on My Foot" (which co-starred Robert Duvall as a drug addict trying to go "cold turkey"). Maharis abruptly left Route 66 during its third season, with the reasons varying as to why. Except for the tense thriller The Satan Bug (1965), his film choices were poor and he returned to television for the short-lived 1970 TV series The Most Deadly Game. He was arrested for "sexual perversion" in 1974, though he continued to act on television after that. His last film appearance was in 1993. He lives in Beverly Hills and New York City and creates impressionist paintings.