Sean Astin

Sean Astin, born Sean Patrick Astin on February 25, 1971, in Santa Monica, California, is an American actor and trade union leader. Born Sean Duke, he was adopted in 1972 by actor John Astin following John's marriage to Astin's mother, actress Patty Duke. His biological father is Michael Tell, a writer, music promoter, and publisher of the newspaper The Las Vegas Israelite, a fact confirmed through a paternity test taken in 1994. At the time of Astin's birth, entertainer Desi Arnaz Jr. had been incorrectly identified as his biological father. Astin has described maintaining close relationships with John Astin, Desi Arnaz Jr., and his stepfather Mike Pearce, as well as Tell. His half-brother, Mackenzie Astin, born in 1973 to Patty Duke and John Astin, also became an actor. Astin is of German, Irish, and Jewish ancestry. He attended Catholic school and later became a Protestant.

Astin was educated at Crossroads High School for the Arts in Santa Monica and completed master classes in acting at the Stella Adler Conservatory in Los Angeles. He attended Los Angeles Valley College before transferring to UCLA, where he graduated cum laude with a bachelor of arts in history and English, with a concentration in American literature and culture.

His first acting role came in the 1981 television film Please Don't Hit Me, Mom, in which he played a child with an abusive mother portrayed by his real-life mother, Patty Duke. His film debut followed at age thirteen, when he played Mikey Walsh in The Goonies (1985). He went on to appear in a series of films throughout the late 1980s and early 1990s, including White Water Summer (1987) with Kevin Bacon, The War of the Roses (1989), the World War II film Memphis Belle (1990), Toy Soldiers (1991), Encino Man (1992), and the college football biopic Rudy (1993), in which he portrayed Daniel Ruettiger.

In 1994, Astin directed and co-produced, alongside his wife Christine Astin, the short film Kangaroo Court, which earned an Academy Award nomination for Best Live Action Short Film. He continued appearing in films through the decade, including the science fiction film Harrison Bergeron (1995), the Gulf War drama Courage Under Fire (1996), and the political satire Bulworth (1998).

Astin's most prominent film work came in the early 2000s, when he portrayed Samwise Gamgee in Peter Jackson's The Lord of the Rings trilogy, comprising The Fellowship of the Ring (2001), The Two Towers (2002), and The Return of the King (2003). He also voiced the character in the video game tie-in to The Return of the King. His performance earned seven award nominations, of which he won five, including the Saturn Award, the Sierra Award, the Seattle Film Critics Award, and the Utah Film Critics Award, all for Best Supporting Actor, as well as the Visual Effects Society Award for Outstanding Performance by a Male or Female in an Effects Film. The Return of the King cast collectively received awards from the National Board of Review of Motion Pictures, the Screen Actors Guild, the Broadcast Film Critics Association, and a Gold Derby Award. Astin's daughter Alexandra appeared in the closing scene of The Return of the King, playing his character's daughter, Elanor. During production, Astin also directed a second short film, The Long and Short of It, with assistance from fellow cast and crew members including Peter Jackson. The film premiered at the 2003 Sundance Film Festival and appears on the DVD release of The Two Towers. In 2004, Astin published a memoir co-written with Joe Layden, There and Back Again, focusing on his experiences during the production of the trilogy.

His television work includes a recurring guest role as Lynn McGill across ten episodes of the fifth season of the Fox drama 24, the voice of the title character in the animated series Special Agent Oso, which aired on Playhouse Disney and Disney Junior from 2009 through 2014, and the voice of Raphael in the Nickelodeon animated series Teenage Mutant Ninja Turtles from 2012 to 2017. He portrayed Bob Newby in the second season of Stranger Things in 2017. Additional television credits include guest appearances on Monk, Las Vegas, My Name Is Earl, and Law & Order, as well as roles in the made-for-TV films Hercules and The Colour of Magic. Astin also directed a 2003 episode of the series Angel, titled "Soulless." His voice work further includes narrating the American version of the Animal Planet series Meerkat Manor and voicing Hercules in the video game Kingdom Hearts.

Astin's acting honors include a Screen Actors Guild Award and two Young Artist Awards, in addition to his Academy Award nomination for Kangaroo Court. Beyond performance, he serves as the fourth national president of SAG-AFTRA, having been elected in 2025 to a two-year term that began in September 2025.

In 2024, Astin made his Broadway debut, appearing in the musical Elf.