Claremont is regarded as one of the hallmark Marvel Comics writers, having written one of the flagship titles, the Uncanny X-Men, for sixteen consecutive years, bringing the title from obscurity to one of the most successful comics of all time. Many of his stories contained the social undercurrent of mutants being a harassed minority. Claremont also promoted strong female characters such as Rogue, Storm and Moira MacTaggert. Claremont's work on X-Men, which was longer than that of any other writer, defined many of the X-Men characters years after his departure from Marvel Comics. Claremont has also written several novels, including the novelization of the second X-Men film, X2. He has a cameo in the film X-Men 3 during the Jean Grey prologue, for which he is credited as "Lawnmower man."
As an entry into comic writing, Claremont was given the fledgling title Iron Fist in 1974, which teamed him with John Byrne. Len Wein then gave him the writing duties for the relaunched X-Men. Claremont found narrative excuses to sideline Professor X, as one of the problems with the original X-Men series was that the Professor often appeared at the end of the story to provide a deus ex machina solution to whatever problem the X-Men faced.
During his years as X-Men writer, Claremont wrote or co-wrote many classic stories such as the "Dark Phoenix Saga" and "Days of Future Past." In addition, he helped launch best-selling spin-offs such as X-Men, New Mutants, Excalibur, and Wolverine. In 1986, Marvel launched an X-Men spinoff, X-Factor, altering the Phoenix/Jean Grey continuity Claremont had established. In 1991 a second X-Men title simply called X-Men (often referred as "adjectiveless" X-Men) was launched having Claremont as writer though he only wrote three issues since he left Marvel following a series of editorial differences with the X-Men editor at the time Bob Harras.
In 1998, he returned to Marvel as editorial director and the regular writer of Fantastic Four. He also wrote a Wolverine story arc. In 2000, as part of the company's "Revolution" event, he wrote Uncanny X-Men and X-Men until he moved to X-Treme X-Men.
In 2006, cardiac illness forced Claremont to postpone the beginning of a planned run on Exiles as well as the launch of GeNext. Also cut short was his run on Uncanny X-Men, which was completed by Tony Bedard over Claremont's plots. Likewise, writer Frank Tieri took over on New Excalibur in Claremont's stead for a time.
In 2007, Claremont returned to New Excalibur, writing a story arc where the character Nocturne has a stroke. He also completed his first arc on Exiles, introducing Psylocke to the team.
Claremont has written many stories for other publishers including the Star Trek Debt of Honor graphic novel, his creator-owned Sovereign Seven for DC Comics and Aliens vs Predator for Dark Horse Comics. He also wrote a few issues of the series WildC.A.T.s at Image Comics, which introduced his creator-owned character, Huntsman.
Outside of comics, Claremont co-wrote the The Shadow War Chronicles trilogy, Shadow Moon (1995), Shadow Dawn (1996) and Shadow Star (1999), with George Lucas. This trilogy continues the story of Elora Danan from the movie Willow. He wrote a science fiction trilogy about female USAF pilot/astronaut Nicole Shea, consisting of First Flight (1987), Grounded! (1991), and Sundowner (1994). Claremont was also a contributor to the Wild Cards anthology series.
Cover of Star Wars Annual (1977) 1, written by Claremont
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