Director Cameron Crowe and Stoltz became friends while making Stoltz's first feature film, Fast Times at Ridgemont High (1982), which Crowe wrote and in which Stoltz had a minor role.
He also produced the films Bodies, Rest & Motion in 1993, Sleep with Me in 1994, and Mr. He continued to appear on the New York stage, both on Broadway (Three Sisters, Two Shakespearean Actors, Arms and the Man) and off-Broadway (The Importance of Being Earnest, The Glass Menagerie, Sly Fox and Our Town).
He was nominated for a Tony Award as Featured Actor for his performance as George Gibbs in the 1989 Broadway revival of Thornton Wilder's Our Town.
In 2004, he appeared in The Butterfly Effect as a child molester; the following year, he guest-starred in the NBC sitcom Will & Grace as Debra Messing's love interest.
He was nominated for a Daytime Emmy for his direction of the cable movie My Horrible Year! Beginning in 2007, Stoltz directed episodes of the drama series Quarterlife, which began airing as webisodes and were then picked up to air on the NBC network in 2008.
In the 1970s Stoltz joined a repertory company that performed ten plays at the Edinburgh Festival.