Bill moved to Los Angeles at 18 where he found work in the film industry as a set dresser for Roger Corman's New World Pictures. He made his film debut in the Corman film Crazy Mama directed by Jonathan Demme. Moving to New York, he studied acting under Stella Adler at New York University. After landing a small role in Stripes, Bill found steady work in low-budget films and TV. He also directed, wrote and produced award-winning short films including Fish Heads which aired on SNL 25. His first appearance in a James Cameron film was a small role in The Terminator followed hard by his very memorable performance as Private Hudson in Aliens and as the nomadic vampire Severen in Kathryn Bigelow's Near Dark. Bill also appeared in John Hughes' Weird Science, as Wyatt's sadistic older brother Chet. Although he continued to work steadily in film and TV, his big break did not come until his lead role in the critically acclaimed film-noir One False Move. This quickly led to strong supporting roles as Wyatt Earp's naive younger brother Morgan in Tombstone and as Fred Haise, one of the three astronauts in Apollo 13, as well as in James Cameron's offering True Lies.
Bill had rheumatic fever in the 7th grade. It kept him hospitalized for a month and bed-ridden for four months. He had to take regular doses of penicillin until he was 18. As a teen, Bill caddied for golf great Ben Hogan in Fort Worth. Has two children with Louise Newbury: James Paxton (b. 1994) and Lydia (b. 19 December 1997). Directed the theatrical short Fish Heads which won a Special Award at the 1982 Melbourne Film Festival. Co-authored and produced the short, Scoop (1983), which won a Honorable Mention at the 1983 USA Film Festival. Member of the 1980s rock band Martini Ranch. James Cameron directed a video for their song "Reach" featuring many Cameron alumni (Kathryn Bigelow, Lance Henriksen, Jenette Goldstein). Son of John Paxton. Met his wife on a number 13 bus in London. Bill's paternal grandfather was friend and neighbor to the great American painter, Thomas Hart Benton. Learned to speak German to prepare for his part in the Pat Benatar video, "Shadows of the Night." Attended Arlington Heights High School in Fort Worth, Texas. The same high school as John Denver and Lee Harvey Oswald (who left before he graduated). In his movies he has been killed by an Alien, a Predator and a Terminator. He has earned the nickname "Wild Bill" among friends and co-stars for his apparently crazed sense of humor and his love for elaborate pranks. Has appeared in five films with Michael Biehn: The Lords of Discipline, The Terminator, Aliens, Navy Seals, Tombstone. Was the only actor to work on both an Alien movie and a Predator movie. Was the first choice as Robert Langdon in The Da Vinci Code. He turned the part down because he was already signed for Big Love. Tom Hanks was cast for the film instead.