He is best known for his roles as Marv Murchins in Home Alone (1990) and Home Alone 2: Lost in New York (1992), Phil Berquist in City Slickers (1991) and City Slickers II: The Legend of Curly's Gold (1994), the voice of adult Kevin Arnold on the television series The Wonder Years, and the voice of Dilbert on the animated series of the same name.

Other notable films of his include Breaking Away (1979), Stardust Memories (1980), Diner (1982), Blue Thunder (1983), Hannah and Her Sisters (1986), The Milagro Beanfield War (1988), Coupe de Ville (1990), and Very Bad Things (1998).

Stern applied for a job as a lighting engineer for a Shakespeare Festival in Washington, D.C., but was hired as a walk-on in their production of The Taming of the Shrew, starring Glenn Close.

However, he declined to play the character once again in the fourth installment of the franchise, believing the script to be a disgrace to the original motion picture.

In 1998, Stern took on a more serious role in the black comedy Very Bad Things with Christian Slater, Cameron Diaz and Jon Favreau.

[5] Stern provided the voice for the main character of the Dilbert animated TV series, based on the comic strip by Scott Adams.

Stern was originally offered the role of Dale Gribble in King of the Hill but he was replaced by Johnny Hardwick when his salary agreement went low.

[10] He has created sculptures for California public art projects in San Diego, Pasadena, Palm Desert, Temple City, Monrovia, and Agoura Hills.