A handsome war veteran who grew up in a Philadelphia orphanage, Johnson spent 14 years playing bad guys in TV and movie westerns. Then he reluctantly agreed to audition for a new comedy series called "Gilligan's Island," a program that would move critics like UPI's Rick DuBrow to declare: "It is impossible that a more inept, moronic or humorless show has ever appeared on the home tube."
The public loved it. Johnson was Professor Roy Hinkley, a stuffy hunk of a scientist who was one of seven castaways on an uncharted Pacific isle. The show lasted three seasons but was subsequently aired in 30 languages and became a perennial rerun.
Johnson became so identified with the bookish, straight-arrow professor that finding other roles became a problem. "After 'Gilligan's Island,' I couldn't get a job playing heavies, let alone getting a job," he told CNN in 1993.
Johnson, who was signing autographs as recently as last month, died in his sleep Thursday at his home on Bainbridge Island, Wash. He was 89.
The cause of his death was not disclosed, but Johnson's agent, Michael Eisenstadt, said it was from natural causes.
The only surviving castaways are Tina Louise, who played the sexpot movie star Ginger Grant, and Dawn Wells, who played Mary Ann Summers, the ponytailed good girl in short shorts. Jim Backus (millionaire Thurston Howell III) died in 1989, Natalie Schafer (Howell's wife, Lovey) in 1991, Alan Hale Jr. (skipper Jonas Grumby) in 1990 and Bob Denver (Gilligan) in 2005.
While the rest of the cast ranged from ditzy to occasionally psychotic, Johnson's buttoned-down professor often played the straight man to Bob Denver's Gilligan, a lovable knucklehead who screwed up nearly everything he touched.
In a typical exchange, Johnson's character — known as the Professor — excitedly talks about his archaeological find: "After treating the tablet with this acid solution, the hieroglyphics will become legible!" he explains.
"And we can read it, too!" Gilligan adds.
Born on Nov. 10, 1924, in Ashley, Pa., Russell David Johnson lived from the time he was 9 until he was 18 at Girard College, a large boys' orphanage in Philadelphia. His father had died and his mother, who had six children, couldn't afford to keep him and one of his brothers at home.
Johnson acted in a production at Girard, but rarely saw movies and was taken with the other boys to only one stage play — "Life With Father" — before graduating from high school in 1942.
During World War II, he served in the Army Air Forces. He was shot down over the Philippines and received a Purple Heart.
Using the GI Bill to study at the Actors' Laboratory in Hollywood, Johnson landed a role in "For Men Only," a 1952 film about hazing in a college fraternity. The next year, he played the black-hat brother to Ronald Reagan's white-hat Arizona marshal in the western "Law and Order."
He also did two episodes of Rod Serling's "Twilight Zone," three westerns with war hero Audie Murphy, and the short-lived western TV series "Black Saddle." Playing the heavy was just fine with him, he told an interviewer for the Archive of American Television in 2004, but he confessed that he was never comfortable on a horse.
In "Gilligan's Island," that wasn't a problem. Although the characters were supposed to be tourists who signed up for an afternoon sea jaunt on the S.S. Minnow, most of the shooting was done indoors at a CBS studio. The Minnow was a play by series creator Sherwood Schwartz on the name of Newton N. Minow, the FCC chairman who gave a famous 1961 speech blasting TV as "a vast wasteland."
After his run on "Gilligan's Island," Johnson found work on many TV episodes, including two seasons of "Dynasty." He moved to Bainbridge Island in 1988 and kept a full schedule of voice-over work and appearances at corporate events.
In interviews, he said he had no regrets about his tenure as the Professor.
The show "satisfied people's fantasies," he told the Houston Chronicle in 1993. "It's fun and funny and not dated."
Asked how it was that the characters brought along so many changes of clothes for what was supposed to be a three-hour tour, he gave an explanation worthy of the old pro he was.
"That's show biz," he said.
Russell is survived by his wife, Connie; his daughter, Kimberly; a stepson, Court Dane; and a grandson.
His son Dave Johnson, the first AIDS coordinator for Los Angeles, died in 1994.