Peter Frederick Weller was born in Stevens Point, Wisconsin, to Dorothy Jean (Davidson) and Frederick Bradford Weller, a federal judge and career helicopter pilot for the United States Army. His father's extensive travels around the world provided Weller with a unique upbringing, as he attended high schools in Heidelberg, Germany and San Antonio, Texas, before enrolling at the University of North Texas.
Weller's interest in music was evident from a young age, as he was attracted to the University of North Texas due to its celebrated jazz bands and the opportunity to play trumpet. Music runs deep in his family, with three generations on his mother's side being piano players. Weller's favorite performer is the legendary Miles Davis.
After graduating from the University of North Texas with a B.A. in Theatre and a scholarship to the American Academy of Dramatic Arts, Weller moved to New York. Two weeks after graduating, he made his Broadway debut in Joseph Papp's New York Shakespeare Festival production of David Rabe's "Sticks and Bones".
Weller continued to hone his craft under the guidance of legendary actress and drama coach, Uta Hagen, appearing in various productions on and off Broadway. He received critical acclaim for his portrayal of Billie Wilson in "Streamers", directed by Mike Nichols for Joseph Papp at Lincoln Center, and for his performances as Cliff in "The Woolgatherer" and as Nick in the first American production of David Mamet's "The Woods".
Weller's film debut was in Richard Lester's Butch and Sundance: The Early Days (1979). He then co-starred with Alan King and Ali MacGraw in Sidney Lumet's Just Tell Me What You Want (1980) and, with Albert Finney and Diane Keaton, in Alan Parker's Shoot the Moon (1982). Other notable film credits include Firstborn (1984) with Teri Garr, the HBO made-for-TV Apology (1986),co-starring Lesley Ann Warren, and Of Unknown Origin (1983),which earned him the Best Actor award at the Paris International Film Festival for his performance as an upwardly mobile bachelor with a serious rat problem.
Weller's early career was marked by his association with the Actor's Studio, under the guidance of Elia Kazan and Lee Strasberg. He has continued to work in film and television, with notable roles in Leviathan (1989) and other projects.