Harry Harrison: Writer of sci-fi novels who created the popular anti-hero the Stainless Steel Rat

Harrison's war experiences left him a convinced pacifist. Several of his protagonists refused to kill

A literary maverick with a prodigious output, Harry Harrison, who has died aged 87, was a published writer for 60 years. To his chosen field of science fiction, he brought humour, irreverence and an informed, occasionally cynical sensibility. In over 100 short stories and 60 novels, he employed dimensionalism alongside a fondness for puns. Never quite at home in his native US, at various times he lived in Italy, Britain, Mexico and Denmark, before basing himself in Ireland; he also wrote under many pseudonyms, one of which was, in effect, his own name.

Born in Connecticut to an Irish-American father and Russian mother, he was christened Henry Dempsey, like his father, and did not legally become Harry Harrison until he was 30. His peripatetic sensibility was inadvertently established when his parents moved to New York when he was two, eventually settling in Queens. Despite his father's variable income as a printer, resulting in several "moonlight flits" and the coining of the family pseudonym Harrison, he said "I cannot remember a time when I could not read."

In addition to science fiction, an early favourite of his was C.S. Forester, whose output would later be reflected in his own A Transatlantic Tunnel, Hurrah! (1972), concerning a descendant of George Washington seeking to establish a railway line under the Atlantic, in an alternate future where America was still a British colony.

After leaving Forest Hills High School in 1943, he was drafted into the Army Air Corps, becoming a sergeant by the end of the conflict. His war experiences left him a convinced pacifist. Several of his protagonists, such as the reformed criminal "Slippery" Jim DiGriz, otherwise known as The Stainless Steel Rat, refused to kill, or expressed great remorse at having to do so. In common with many other science fiction writers, he would be strongly opposed to the war in Vietnam.

Deciding "my fate was in the arts, but whether in writing or painting I could not be sure... art won", he enrolled in Hunter College in NYC in 1946, dropped out but "within the year I was a hard-working comic-book hack". Harrison later said that his position on comics was "somewhere back among the molars in the horse's mouth". His illustrations included a 1950 comic book of Dr Jekyll and Mr Hyde, and, decisively, Galaxy Science Fiction. From editing then-thriving sensationalist "pulp" collections, then penning them himself, he started to write in his chosen genre.

His first short story, "Rock Diver", was published in 1951, in Worlds Beyond, a magazine he had been illustrating for. While still in New York, he socialised with fellow sci-fi practitioners at the Hydra Club, including Isaac Asimov, whose work he would parody in Bill, the Galactic Hero (1965) and its sequels. Taking the decision to become a freelance writer, in 1956 he drove to Mexico in his Ford Anglia, and settled there.

By 1957, his short-story output had included the Stainless Steel Rat's debut, initially published in the long-running magazine Astounding, whose editor, John W Campbell, was inspirational as a friend and mentor, urging him to complete what became his first published novel, Deathworld (1960).

While living in Denmark in the early 1960s, he ghost-wrote several stories for The Saint Mystery Magazine, officially credited to Simon Templar's creator Leslie Charteris. A subsequent novel bearing Charteris's name, Vendetta for the Saint (1964), was actually written by Harrison, having begun as a comic strip. Four years later, it was made as a two-part story in the ATV/ITC series starring Roger Moore (and, edited, released in cinemas outside Britain), but Harrison was not credited or remunerated for this; it had been "for a lump sum, no royalties".

The Stainless Steel Rat made his hardcover debut in 1961. Mirroring his early career, some of the novels, including The Stainless Steel Rat for President (1982), were serialised in the British comic 2000 AD in the 1980s. Harrison was still busying himself with the character in 2010. West of Eden (1984), in which dinosaurs had never died out and had become the dominant species, had two sequels. Controversially, his short story "The Streets of Ashkelon", with an atheist (like Harrison himself) as protagonist and a missionary who teaches aliens Christianity only for them to crucify him, was not published in America until 1968, six years after its British publication.

Back in playful mode, Star Smashers of the Galaxy Rangers (1973) culminated in its heroes, Chuck and Jerry, becoming gay lovers. With his great friend and contemporary Brian Aldiss, Harrison edited several anthologies, including Hell's Cartographers (1975). It took its title, and remit, from Kingsley Amis's critical study New Maps of Hell (1960); in return, Amis once claimed that Harrison was "incapable of writing a dull sentence."

Regarding films from his work, Harrison was less lucky than certain of his contemporaries. Make Room! Make Room! (1966) reflected his deep concerns about overpopulation; while its adaptation, Soylent Green (1973), directed by Richard Fleischer and starring Charlton Heston was not unsuccessful commercially, Harrison felt that MGM "gutted my book like a dead fish" and "reduced [it] down to a cannibalism tale." (The changed title refers to a compound, in the book, that Harrison got from combining soy beans and lentils.)

In his introduction to Future Tense (1978), a study of science fiction cinema by critic and friend John Brosnan, Harrison maintained that most genre screenwriters actually know nothing about science, hence contrived results. The Technicolor Time Machine (1967), in which studio moguls encounter Vikings, included the line "Hollywood is not dead, it's just very, very sick."

An unmistakeable figure with his goatee beard, bald head and glasses, he was a frequent and popular guest at science-fiction conventions. His wife, Joan, predeceased him in 2002. He is survived by his son, Todd, and daughter, Moira. Make Room! Make Room! had been dedicated to his children: "For your sakes... I hope this proves to be a work of fiction."

Henry Maxwell Dempsey (Harry Max Harrison), writer: born Connecticut 12 March 1925; married first Evelyn (marriage dissolved), second 1956 Joan Merkler (died 2002, one son, one daughter); died Brighton 15 August 2012.