1. He is best known for roles in films including; Reality Bites, Forces of Nature, Happy, Texas, Joy Ride, Riding in Cars with Boys, Daddy Day Care, National Security, Sahara, A Perfect Getaway, Dallas Buyers Club, and played Frank Heffley in the Diary of a Wimpy Kid film series.
2. He is also known for lending his voice to Stuart Little, Stuart Little 2, Dr. Dolittle 2, Escape from Planet Earth, Chicken Little, The Good Dinosaur, and voiced Swampy and Sherman on the family television series Phineas and Ferb, and played Cobi on Mad Dogs .
3. Zahn was born in Marshall, Minnesota, the son of Zelda, who worked for the YMCA, and Carleton Edward Zahn, a retired Missouri Synod Lutheran pastor. Zahn spent part of his childhood in Mankato, Minnesota, attending Kennedy Elementary School, and later moved to the suburbs of Minneapolis.
4. After attending Robbinsdale Cooper High School, Gustavus Adolphus College, and the Institute for Advanced Theater Training at American Repertory Theater at Harvard University, his first professional acting role was in Biloxi Blues, a Minnesota production at the Old Log Theater; but his first big break came in 1994, when he was noticed by actor/director Ben Stiller, who cast him in his picture, Reality Bites.
5. From 1992 to 1993, he toured as Hugo with the Barry Weissler production of Bye Bye Birdie with Tommy Tune, Ann Reinking, and Marc Kudisch.
6. These films garnered him enough respect that he was offered the starring role in the critically acclaimed indie film Happy, Texas .
7. Zahn received his strongest critical acclaim for his performance in Riding in Cars with Boys, in which he co-starred with Drew Barrymore as her dim-witted, drug addicted husband.
8. Roger Ebert, Richard Roeper and the BBC stated that the performance was deserving of an Oscar nomination.
9. He also gave dramatic performances in Rescue Dawn and the television mini-series Comanche Moon.
10. Typically typecast into comic relief sidekick roles, Zahn was asked if he minded, his reply was that it was a “pleasure” and a “privilege,” saying: “to be typecast and make money and make people happy and people dig what you do, what a great thing, man.”
11. On July 16, 1994, Zahn married Robyn Peterman, an actress and the daughter of entrepreneur John Peterman, whom Zahn met on a touring production of Bye Bye Birdie.
12. They have a son, Henry James Zahn, born on April 3, 2000, and a daughter, Audrey Clair Zahn, born on April 25, 2002.
13. On May 4, 2007, he was conferred an honorary Ph.D. in Fine Arts, from Northern Kentucky University.