Russell Johnson, the veteran TV actor best known for playing Professor Roy Hinkley on 'Gilligan's Island,' passed away today from natural causes. He was 89.

Born in 1924, Johnson's acting career began in 1950 following a highly decorated stint in the United States Air Force, where he flew dozens of combat missions during World War II. He worked steadily throughout the '50s and '60s, appearing in countless TV shows and movies, eventually becoming a regular on 'Black Saddle' in 1959. He was cast as the Professor in 'Gilligan's Island' in 1964 and the rest is TV history. Every TV fan has joked at least once about how the Professor could build all kind of technology out of scraps but couldn't fix the slightly damaged boat that had stranded him and his shipmates.

Although 'Gilligan's Island' ended up being his definitive role (and one that he embraced whole-heartedly), he continued to work, appearing on shows like 'The Twilight Zone,' 'Dallas,' 'Gunsmoke,' 'Wonder Woman,' 'The Jeffersons,' 'MagGuyver,' 'Newheart,' 'Dynasty' and 'Alf.' He stepped away from acting in 1997.