George Clayton Johnson: Screenwriter best known for Logan's Run who also wrote Star Trek opening episode

George Clayton Johnson was the novelist and screenwriter best known as co-author of the 1967 book Logan's Run, written with William F Nolan, which inspired the hit 1976 science-fiction film of the same name. "For me, fantasy must be about something, otherwise it's foolishness," Johnson said. "Ultimately it must be about human beings, it must be about the human condition, it must be another look at infinity, it must be another way of seeing the paradox of existence."

Johnson was born in 1929 in Cheyenne, Wyoming. After dropping out of college he served in the US Army as a draughtsman and telegraph operator before enrolling at Alabama Polytechnic Institute. His break into writing for TV came with "I'll Take Care of You", an episode for the popular thriller series Alfred Hitchcock Presents, broadcast on CBS in 1959.

His first major film success came the following year with Ocean's 11 (1960), a story he had written while running Café Frankenstein, a notorious hang-out for beatniks and surfers in Laguna Beach, California. The plot sees Danny Ocean's crew of 11, including most of Frank Sinatra's "Rat Pack", plan a heist on five Las Vegas casinos on the same night. When Sinatra, who played Ocean, first heard of the film he joked, "Forget the movie, let's pull the job!" It was remade in 2001 starring George Clooney and Brad Pitt, with ex-cons replacing ex-soldiers as the team of crooks.

In the early 1960s Johnson joined a group known as the Southern California School of Writers. Among their members was the science fiction author, Ray Bradbury, who Johnson credited with giving him a belief in himself as a writer. Nolan recalled of the group, "We'd talk plot, read stories we'd finished for opinions, talk about markets and what was selling and who was buying, discuss character development and structure – and, yes, we'd argue, but in a constructive way."

Johnson was commissioned by the Twilight Zone producer, Rod Serling, to write eight episodes of the mystery series. "The Twilight Zone played just as much a part in the renaissance transformation of the Sixties as bright-coloured clothing, rock music and marijuana did," Johnson noted, "It helped to jack people up to a higher level."

His work for The Twilight Zone brought him to the notice of the Star Trek associate producer John DF Black, who asked him to write for the story "The Man Trap", aired in September 1966 as the first broadcast episode of the sci-fi series. Playing on themes of psychology, love and a shape-shifting half-woman/half-monster who craves salt, the episode echoed existential ideas that he had already explored in The Twilight Zone and was quite distinct from subsequent Star Trek storylines.

Logan's Run, written by Johnson and Nolan, was first published as a novel in 1967. In this dystopian vision of life in the 23rd century, the citizens of a domed city are assigned a life span of 21 years, measured by a coloured palm-flower crystal implanted in their hand. As the crystal turns to black they must submit to being "renewed", a euphemism for death by vaporisation.

Michael Anderson's 1976 film adaptation, which has become a cult classic, starred Jenny Agutter, and Michael York in the role of Logan 5, a "sandman" whose role is to seek out the "runners" who try to escape their death sentence. When the master computer shortens his life by four years, Logan becomes a runner himself and seeks refuge in the outside world with fellow escapee Jessica.

In 2003 Johnson said, "I want to be remembered as a person who early on in his life took control of his life and set goals. When people gave me a lined paper, I wrote the other way. When people expect some certain behaviour from me, I will frustrate their expectations."

Johnson had been a long-time advocate of cannabis legalisation. He described its use in the creative process: "I sit down and I smoke a little bit of pot. As I'm smoking the pot I suddenly begin noticing things... looking deeper into reality than you were before and I keep this up until I get into a state of total mental excitement... I think prohibition of any kind is dumb." He lived to see cannabis made legal for recreational use in four US states.

His agent Whitt Brantley told The Independent that a remake of Logan's Run is in the works and that Johnson had been developing a follow-up, Jessica's Run. "George always believed the original novel needed a third act. Jessica's Run is that third act," he said. He said of Johnson: "He was a such a sweet guy but he had a backbone made out of steel and one of the most beautiful minds I've ever known. What is it Nicholas Hilliard said about Sir Francis Bacon? Si tabula daretur digna, animum mallem: 'If one could but paint his mind!'"

George Clayton Johnson, novelist and screenwriter: born Cheyenne, Wyoming 10 July 1929; married 1952 Lola Brownstein (one daughter, one son); died North Hills, California 25 December 2015.