William Petersen Bio
William Louis Petersen (born February 21, 1953) is an American retired actor and producer widely recognized for portraying forensic scientist Gil Grissom on the CBS crime drama CSI: Crime Scene Investigation, a role he played from 2000 to 2015 and later reprised in the sequel series CSI: Vegas. Across a career spanning more than four decades, he balanced screen work with a deep commitment to theater, including long-running ties to Chicago’s celebrated Steppenwolf Theatre Company. He announced in October 2025 that he is retired from acting and is not pursuing new roles.
Born in Evanston, Illinois, and raised partly in Idaho, Petersen trained as a Shakespearean actor before moving into film and television. His body of work includes a string of notable 1980s and 1990s features, a defining run on one of television’s most-watched procedurals, and a return engagement that closed out his on-screen career.
Early Life and Background
William Louis Petersen was born on February 21, 1953, in Evanston, Illinois, the youngest of six children of June Hoene (1909–2006) and Arthur Edward Petersen (1907–2004), who worked in the furniture business. Of Danish and German descent, he was raised in the Roman Catholic faith of his mother. He has two brothers, Arthur Jr. and Robert, and three sisters, Anne, Mary Kay, and Elizabeth.
He graduated from Bishop Kelly High School in Boise, Idaho, in 1972, and was accepted to Idaho State University on a football scholarship. While at Idaho State, Petersen took an acting course that redirected his ambitions toward the stage. In 1974, he and his wife Joanne left college and followed a drama professor to the Basque country, where he studied as a Shakespearean actor. He grew interested in Basque culture, studied the language, and gave his daughter the Basque name Maite Nerea, meaning My Beloved; she was born in Arrasate/Mondragón in 1975.
Path to Celebrity
Returning to Idaho with the intention of becoming an actor, Petersen decided not to settle for non-acting work there and moved back to the Chicago area to live with relatives. He became active in the regional theater scene and earned his Actors’ Equity card. He performed with the Steppenwolf Theatre Company, of which he became an ensemble member in 2008, and was a co-founder of the Remains Theater Ensemble, alongside other prominent Chicago actors including Gary Cole and Ted Levine.
These years on Chicago stages shaped his disciplined approach to character work, and his reputation for intense preparation soon translated into film opportunities. By the mid-1980s he was working with leading directors and moving between Hollywood features and the Chicago theater community that had trained him.
William Petersen Career
Early Career (1976–1989)
Petersen made his film debut with a bit part in Michael Mann’s Thief (1981). His first major break came when he played a Secret Service agent gone rogue in William Friedkin’s 1985 action film To Live and Die in L.A. He followed that with the role of FBI profiler Will Graham in Mann’s 1986 Hannibal Lecter film Manhunter, a performance he later described as so emotionally exhausting that he changed his appearance to separate himself from the character.
During this period he also turned down roles he felt would take him away from his family, including a part in Oliver Stone’s Platoon, and instead appeared in the 1987 HBO made-for-TV movie Long Gone, in which he played a minor league baseball player and manager. He also reportedly turned down the role of Henry Hill in Goodfellas.
Breakthrough (1990–2000)
In 1990, Petersen portrayed Ambassador Joseph P. Kennedy Sr. in the ABC miniseries The Kennedys of Massachusetts, a production that won an Emmy and a Golden Globe. That same year, he played the infamous Pat Garrett in Young Guns II. He later appeared in the 1993 CBS miniseries Return to Lonesome Dove as former Ranger Gideon Walker, and in 1996 starred as a desperate father in Fear. He also featured in the 1997 remake of 12 Angry Men and appeared uncredited in the noir thriller Mulholland Falls.
His most career-defining turn arrived in 2000, when he was cast as Dr. Gil Grissom on CSI: Crime Scene Investigation. The role brought him widespread recognition, a Screen Actors Guild Award, and a Golden Globe nomination. He also earned three Primetime Emmy nominations as a producer of the series.
Notable Works and Milestones
Petersen’s signature work is CSI: Crime Scene Investigation, where his understated portrayal of the cerebral Gil Grissom helped define the forensic procedural era of prime-time television. He renewed his contract with CBS for the 2008–09 season at a reported $600,000 per episode, and in 2009 he received a star on the Hollywood Walk of Fame. He stepped away from the series as a regular after Season 9 but remained an executive producer and returned for the 2015 series finale.
William Petersen Award Nominations
Throughout his career, William Petersen earned recognition from major industry bodies, including a Golden Globe nomination and three Primetime Emmy nominations for his work as a producer on CSI: Crime Scene Investigation.
William Petersen Awards Won
Petersen won a Screen Actors Guild Award for his performance as Gil Grissom on CSI: Crime Scene Investigation. The series itself, in which he also served as a producer, collected additional industry honors during his tenure.
William Petersen Family
William Louis Petersen was born to Arthur Edward Petersen and June Hoene, the youngest of six children that included brothers Arthur Jr. and Robert and sisters Anne, Mary Kay, and Elizabeth. He married Joanne Brady in 1975, and the couple had a daughter, Maite, before later divorcing. In June 2003, he married his longtime girlfriend Gina Cirone, and on July 5, 2011, the couple welcomed twins, a daughter and a son, born via surrogate.
Personal Life
Petersen has long been associated with the Chicago theater community, where he developed his craft and built his reputation as a stage actor alongside his screen career. He was hospitalized in August 2021 after feeling unwell on the set of CSI: Vegas, an episode attributed to exhaustion after twelve weeks of shooting, and was released soon after. In October 2025, he publicly confirmed that he is retired from acting and is not seeking any new roles.