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.