Sean Astin (born February 25, 1971) is an American film actor, director, and producer best known for his film roles as Mikey Walsh in The Goonies, the title character of Rudy, and Samwise Gamgee in the Lord of the Rings trilogy. In television, he appeared as Lynn McGill in the fifth season of 24. Most recently, he provided the voice for the title character in Disney's Special Agent Oso.
Astin was born Sean Patrick Duke in Santa Monica, California, the son of actress Patty Duke. At the time, it was reported that Desi Arnaz, Jr. was his biological father; in 1994, he discovered that he was fathered by Michael Tell, a music promoter and writer who edits and publishes the Jewish newspaper The Las Vegas Israelite. Tell's marriage to Patty Duke was annulled shortly before her marriage in 1972 to actor John Astin, who adopted Sean. Although Patty Duke and John Astin divorced in 1982, Sean Astin has written as an adult that he has always considered John his "real" father and continues to do so. In 1973, Duke gave birth to Astin's half-brother Mackenzie Astin, also an actor.
Astin graduated from UCLA with a B.A. in History and English (American literature and culture). He is an alumnus of Los Angeles Valley College and now serves on the school's Board of Directors of the Patrons Association and the Arts Council. He attended St. Paul the Apostle Elementary School, Bellagio Road Elementary, and the Crossroads High School for the Arts, and participated in master classes at the Stella Adler Conservatory in Los Angeles.