He attended Williams College, where a small incident provided an inkling as to his future career. In 1972, while participating in the school's biannual trivia contest, Sayles' team was tied with another after eight hours, forcing the game's first sudden death overtime. Sayles was able to cite a particular line of dialogue from the 1960 film The Time Machine, thus clinching that semester's championship.
In 1983, after the films Baby It's You (starring Rosanna Arquette) and Lianna (a sympathetic story in which a married woman becomes discontented with her marriage and falls in love with another woman), Sayles received a MacArthur Fellowship for $40,000 a year for a five-year term. Sayles used the money to fund The Brother from Another Planet, a film about a black, three-toed slave who escapes from another planet and finds himself at home among the people of Harlem in New York City, largely because he is incapable of speaking.
In 1989 he created and wrote the pilot episode for the short-lived television show Shannon's Deal about a down-and-out Philadelphia lawyer played by Jamey Sheridan. Sayles received a 1990 Edgar Award for his teleplay for the pilot. The show only lasted 16 episodes before being cancelled in 1991. Sayles has funded most of his films by writing genre scripts such as Piranha, Alligator, The Howling and The Challenge. One such script, for an unproduced film called Night Skies, inspired the project that would eventually become the film E.T. the Extra-Terrestrial. That film's director, Steven Spielberg, later commissioned Sayles to write the script for the forthcoming Jurassic Park IV.
In deciding whether to take a job, Sayles reports that he concerns himself mostly with whether there is the germ of an idea for a movie that he would want to watch. Sayles gets the rest of his funding by working as a script doctor; he has done rewrites for Apollo 13, The Fugitive, and Mimic, among others, and finds the job rewarding since he gets to help other writers tell their stories and also meet other directors and watch how they work. Some of his own better-known films include Lone Star, Passion Fish, Eight Men Out, The Secret of Roan Inish, and Matewan. His films tend to be politically aware; social concerns are a theme running through most of his work. He serves on the advisory board for the Austin Film Society.
In November 1997 the National Film Preservation Board of the United States announced that Return of the Secaucus 7 would be one of the 25 films selected that year for preservation in the National Film Registry at the Library of Congress.
Sayles has recently stated that he would stop directing films, as writing literature offers him a bigger range of opportunities.
John Sayles, Thinking in Pictures: The Making of the Movie Matewan, Da Capo Press, 2003