Erwin was born in Honey Grove, Texas. He attended San Angelo College before earning his bachelor’s degree in journalism at University of Texas at Austin, graduating in 1935. He completed a masters of theater arts in California at the Pasadena Playhouse in 1941. After serving as a Captain in the United States Army Air Corps in World War II, Erwin returned to Hollywood to resume his acting career. His first film role was in 1942 in “You’re in the Army Now”, with Phil Silvers. In the late 1950s, Erwin was in such films as Man from Del Rio (1956) and The Night Runner (1957), before playing Jack Nicholson’s father in The Cry Baby Killer, Nicholson’s first starring role in 1958. The long out-of-print film was released on DVD on November 22, 2006. He had credited small roles in films such as The Christine Jorgensen Story (1970), How Awful About Allan (1970), Candy Stripe Nurses (1974) and Tarantulas: The Deadly Cargo (1977), before he co-starred alongside Christopher Reeve and Jane Seymour in the 1980 romantic fantasy Somewhere in Time as Arthur Biehl, the Grand Hotel’s venerable bellman, and attended annual reunions of cast, crew, and fans of the film at the Grand Hotel on Mackinac Island, Michigan. Erwin also appeared in numerous films by John Hughes, with cameos in Planes, Trains and Automobiles (1987), She’s Having a Baby (1988), Home Alone (1990), and Dennis the Menace (1993). Hughes often paired him with Billie Bird playing his wife. His later film career included roles in Invitation to Hell (1984), Naked Gun 33⅓: The Final Insult (1994), Things to Do in Denver When You’re Dead (1995), Menno’s Mind (1997), Chairman of the Board (1998), Forces of Nature (1999), Inferno (1999) and A Crack in the Floor (2001).

His television credits were far more numerous in the 1950s, having appeared in such television series as I Love Lucy, Crusader, Trackdown, Colgate Theatre, Perry Mason and The Rifleman. In the 1960s, Erwin appeared in television series such as: The Andy Griffith Show, Mister Ed, Maverick, The Twilight Zone, 87th Precinct, The Fugitive, and Mannix. In the 1970s, 1980s and 1990s, he appeared in Barnaby Jones, Cannon, Gunsmoke,(Married With Children as William H Massey ) E/R, Highway to Heaven, Who’s The Boss?, Growing Pains, Full House, The Golden Girls, Moonlighting, and Star Trek: The Next Generation. In Star Trek: The Next Generation, Erwin played Dr. Dalen Quaice, a friend and mentor of Dr. Beverly Crusher. He was the first character to disappear in the episode “Remember Me”. In the Seinfeld episode (“The Old Man”), for which Erwin received an Emmy nomination for outstanding guest actor, he played Sid Fields, who participates in the Foster-A-Grandpa Program, which pairs him with Jerry Seinfeld. Erwin’s crochety, aggressive, foul-mouthed character ensures that the relationship is doomed from the beginning. Erwin later reunited with Michael Richards when he guest-starred on the short-lived The Michael Richards Show. In the 2000s, Erwin appeared on Monk, The West Wing, The King of Queens, Everwood and My Name Is Earl. He lived in the Hollywood Hills with his wife, actress/journalist Fran MacLachlan Erwin (who predeceased her husband). The couple had two sons, Michael and Timothy, and two daughters, Lindsey Thomas Erwin and Kelly Erwin. Erwin had a sister, Mary Gene Cosper. Bill Erwin died at his home on December 29, 2010, in Studio City, Los Angeles from natural causes, near the production lot where Seinfeld was filmed.