(CNN) -- Actor Russell Johnson, best known as Professor in the 1960s TV sitcom "Gilligan's Island," died Thursday, his agent said. Johnson was 89.
Johnson played the iconic role of Professor Roy Hinkley, whose scientific schemes to get the castaways rescued were always foiled by Gilligan's bumbling.
He died at his home in Washington, where he lived with his wife, Connie. She and their daughter, Kimberly, were at his side, said agent Mike Eisenstadt. Johnson is also survived by a stepson, Court, and a grandson, he said.
Johnson worked up until his death, signing autographs over the holidays, said Eisenstadt. He called Johnson's death "unexpected."
He was "just a positive and nice guy" who always treated people with respect, his agent said.
His acting career began in the early 1950s with many jobs as a character actor on television. He played Marshal Gib Scott in two seasons of "Black Saddle," a Western that ran in 1959 and 1960.
Johnson acted in dozens of television shows after the four seasons on "Gilligan's Island," but his career seemed stranded on its own island because of the popular sitcom role.
A noteworthy big screen role was the 1955 science fiction film "This Island Earth." Similar to the story of the shipwrecked passengers and crew of "Gilligan's Island," Johnson played a nuclear physicist involved in building a rocket to take survivors of a doomed Earth to another planet.
Johnson was in Ray Bradbury's 1953 sci-fi classic "It Came From Outer Space."
Before becoming an actor, John served in the U.S. Army Air Forces during World War II. He was on a B-24 Liberator when it was shot down during a bombing raid over the Philippines in 1945, according to his official biography, and used his G.I. Bill benefits to pay for acting school after the war.