NEW YORK — Actor Russell Johnson, who became known to generations of TV fans as “The Professor,” the fix-it man who kept his fellow “Gilligan’s Island” castaways supplied with gadgets, has died. He was 89.

Johnson died Thursday at his home in Washington state of natural causes, said his agent, Mike Eisenstadt.

Johnson was a busy but little-known character actor when he was cast in the slapstick 1960s comedy about seven people marooned on an uncharted Pacific island.

He played high school science teacher Roy Hinkley, known to his fellow castaways as The Professor. There was seemingly nothing he couldn’t do when it came to building generators, short-wave radios and other contraptions from scraps of flotsam and jetsam he found on the island.

But, as Johnson would joke years later, the one thing The Professor never accomplished was figuring out how to patch the hole in the bottom of the S.S. Minnow so the group could get back to civilization.

During its three-season run on CBS, critics repeatedly lambasted the show as insipid. But after its cancellation in 1967, it found generations of new fans in reruns and reunion movies.

One of the most recent of the reunion films was 2001’s “Surviving Gilligan’s Island: The Incredibly True Story of the Longest Three-Hour Tour in History,” in which other actors portrayed the original seven-member cast while Johnson and two other surviving cast members narrated and reminisced.

In later years, Johnson and other cast members, including Bob Denver, who had played the bumbling first mate Gilligan, often appeared together at fan conventions.

Johnson, Dawn Wells and Tina Louise were the last of the cast’s survivors.

Wells played vacationing farm girl Mary Ann Summers and Louise was sexy movie star Ginger Grant.

Besides Denver, the other stars were Alan Hale Jr. as Skipper Jonas Grumby and Jim Backus and Natalie Schafer as snooty millionaires Thurston and Lovey Howell.