David Krumholtz began his acting career at the age of 13 when he followed his friends to an open audition for the Broadway play Conversations with my Father (1992). He won the role of Young Charlie opposite Tony-winner Judd Hirsch, and actors Tony Shalhoub and Jason Biggs (also making his Broadway debut).

Soon after his run on Broadway, David co-starred in two feature films: Life With Mikey (1993) opposite Michael J. Fox and Addams Family Values (1993) opposite Christina Ricci. For his role in Mikey, David was nominated for a 1993 Young Artist Award. Although his work in these two films garnered him critical attention, David is probably best known by children and the young-at-heart as the sarcastic head elf Bernard from The Santa Clause (1994) and its 2002 sequel The Santa Clause 2.

In 1994, David co-starred in his first television series, Monty, with Henry Winkler. The show only lasted a few episodes. David would star in several short-lived series over the years. Along the way, he had the opportunity to work with Jason Bateman (Chicago Sons, 1997), Tom Selleck (The Closer, 1998), Jon Cryer (The Trouble with Normal, 2000), and Rob Lowe (The Lyon's Den, 2003). In 2005, he finally found television success with the CBS series "NUMB3RS", now renewed for a 2006-2007 third season. Along with his starring roles on television, David made memorable guest appearances on ER, Law and Order, Undeclared, Lucky, and Freaks and Geeks.

David amassed a healthy filmography in addition to his television work. He broke out of the children's movie genre with The Ice Storm (1997), directed by Ang Lee, and Slums of Beverly Hills (1998), starring Alan Arkin and Natasha Lyonne. In 1999, David starred as Michael Eckman in the popular teen movie 10 Things I Hate About You with Joseph Gordon-Levitt and Heath Ledger. That same year, he portrayed a completely different teen character - that of Yussel, a young conflicted Jewish man in Liberty Heights.

It was the role of Yussel that brought David to the attention of actor and filmmaker Edward Burns, who cast him in the 2001 independent movie Sidewalks of New York. Playing the romantic and slightly obsessed Benny, David was on a path to larger, more complex film roles. His first role as a leading man was in the 2002 romantic comedy You Stupid Man, playing opposite Milla Jovovich. Although never released theatrically in the United States, You Stupid Man, directed by Edward Burns's brother Brian Burns, was released on DVD in 2006. David carried his first leading role in a released American film when he starred Big Shot: Confessions of a Campus Bookie, which premiered on FX Networks in 2002.

Big Shot was a true story based on the Arizona State University basketball fixing scandal of the Early 1990s. David played Benny Silman, a college student and campus bookmaker who was jailed for his part in shaving points off key ASU basketball games. Benny was unlike any character David played prior, and garnered critical praise for his performance, proving that he was not just a sidekick.

In 2004, David reunited with Edward Burns for the independent film The Last Hold-Outs. The following year he played Max in My Suicidal Sweetheart (formerly Max and Grace), once again starring opposite actress Natasha Lyonne. David also returned to smaller key roles in the successful films Ray and Harold and Kumar Go to White Castle - two very different movies released in 2004. In September 2005, he was seen in Joss Whedon's science fiction film Serenity as Mr. Universe. Most recently, in early 2006, David's 2003 film Kill the Poor screened in New York City at IFC Center and across the country on Comcast's On Demand cable service.

Currently, David is working on the hit series NUMB3RS. He plays Charlie Eppes, a mathematical genius who helps his brother Don (Rob Morrow), an FBI agent, solve crimes using math. The cast of NUMB3RS also includes Judd Hirsch, the man who gave David his start in acting back in 1992 on the Broadway stage. Television critic Matt Roush (TV Guide) called David's work on NUMB3RS "probably his best TV work to date."

David currently resides in Los Angeles, California where he films NUMB3RS.