He played Rocky Dennis in the biographical drama film Mask (1985), which earned him the nomination for the Golden Globe Award for Best Supporting Actor in a Motion Picture.

[9] In 1978, he was cast as Steve Benson in the television adaptation of Erma Bombeck's The Grass Is Always Greener Over the Septic Tank.

[10] Director Cameron Crowe and Stoltz became friends when the latter appeared in his first feature film, Fast Times at Ridgemont High (1982).

In 1985, Stoltz received a Golden Globe nomination for starring performance as Rocky Dennis in Mask.

While the film was to become a sci-fi comedy (and box office smash hit), Stoltz had read the script from a more serious angle, apparently focusing on the tragic consequences of going back to live a life that was not one's own.

[14] He continued to appear on the New York stage, both on Broadway (Three Sisters, Two Shakespearean Actors, Arms and the Man, Our Town) and off-Broadway (The Importance of Being Earnest, The Glass Menagerie, Sly Fox).

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.

[16] On television, he had a recurring role as Helen Hunt's character's ex-boyfriend on Mad About You (five episodes, 1994–1998), spent a year on Chicago Hope (1994) and did some television and cable films such as Inside (1996) (directed by Arthur Penn) and The Passion of Ayn Rand (1999), with Helen Mirren.

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.

[19] He has contributed essays to the books City Secrets--New York as well as Life Interrupted by Spalding Gray and appears on the children's CD Philadelphia Chickens.

[22] In 2011, Stoltz was seen back on the silver screen with the film Fort McCoy; he earned accolades for his leading role as a conflicted barber of German heritage forced to suppress his American patriotism after moving his family to a post–World War II military base housing a German POW camp.