Blonde and boyishly handsome with an easygoing yet uproarious comic flair, Big has added spark and charm to film roles since his early 1990s debut. The Minnesota native got his professional start in dinner theater appearing in a local production of Neil Simon's comedy "Biloxi Blues", and went on to train for two years at the American Repertory Theater in Cambridge, Massachusetts. After a 1991 move to New York, Zahn toured in "Bye Bye Birdie", starring Tommy Tune, Ann Reinking and his future wife Robyn Peterman, and appeared Off-Broadway in the plays "Sophistry" (1993, co-starring Ethan Hawke and Eric Bogosian's "subUrbia" (1994).

While featured in a number of TV roles, including a 1995 guest part on "Friends" (NBC) as Phoebe's Canadian green card husband Duncan, a spot in one of HBO's "Subway Stories" (1997) and a supporting role in the Tom Hanks produced miniseries "From the Earth To the Moon" (HBO, 1998), Zahn is best known for his work on the big screen. The actor's film career began with an appearance in the 1992 political drama "Rain Without Thunder", playing the frightened boyfriend of a girl prosecuted for having an abortion in a future society where the procedure has been outlawed. Perhaps more memorable was his work in Ben Stiller's "Reality Bites" (1994), a role the actor got after being noticed on stage with Ethan Hawkein "Sophistry". Surely one of the more charming characters in "Reality Bites", Zahn's Sammy, a sexually repressed gay man, was both warm and funny. Next up was "That Thing You Do!" (1996) where the actor shone, giving a stand out performance as goofy, girl-crazed lead guitarist Lenny in Tom Hanks' directorial debut. The following year, Zahn re-created his role of Buff, the New Age rollerblader, in Richard Linklater's adaptation of the Bogosian play "subUrbia". 1998 was a busy year for the actor, with no less than four notable releases. The acclaimed "Safe Men", an indie comedy set in Providence, Rhode Island, featured an on-target Zahn and Sam Rockwellas untalented singers who are mistaken for safe crackers by the Jewish Mafia. He particularly impressed critics and moviegoers with his hilarious take on stoner convict Glenn Michaels in Steven Soderbergh's hip crime dazzler "Out of Sight" before rounding out the year with supporting roles in the romantic comedies "The Object of My Affection" (playing Paul Rudd's womanizing brother) and "You've Got Mail", reteaming with Hanks in a remarkably funny, albeit brief, performance as a turncoat bookshop worker. Zahn received acclaim and a special award at the 1999 Sundance Film Festival for his comedic work as one of two escaped convicts (the other played by Jeremy Northam) posing as gay directors in a small town in "Happy, Texas". As Wayne Wayne Wayne Jr., Zahn proved a capable leading man, easily carrying the film through its rough spots with his charismatic performance. He continued his winning streak featured as Ben Affleck's best buddy in "Forces of Nature", undertaking a featured role in John Woo's untitled "Mission: Impossible" sequel and contributing his vocal talents to the live-action/CGI children's film "Stuart Little" (all 1999). The comedy "Running With Scissors" (lensed 1999) saw Zahn team up with past co-stars Tom Everett Scott and Sam Rockwell He was also paired with Dechen Thurman (Uma's brother) as Rosencrantz and Guildenstern in Michael Almereyda's modern day version of "Hamlet" (2000), with Ethan Hawkein the title role. In 2001, Zahn received raves for protraying the laid-back husband to Drew Barrymore's character in "Riding in Cars with Boys." He then joined Martin Lawrence for the buddy comedy "National Security" (2003). In "National Security" Zahn portrayed a white cop who was falsely accused of taking part in a Rodney King-esque police beating.