Krumholtz was born in Queens, New York City. He is the son of Judy and Michael Krumholtz, a dental assistant and a postal worker respectively. He grew up in a "very working-class, almost poor" Jewish family. His paternal grandparents had emigrated from Poland, and his mother moved from Hungary to the U.S. in 1956.\n', '
At the age of 13, Krumholtz followed his friends to an open audition for the Broadway play Conversations with My Father (1992). When he tried out, he won the role of Young Charlie, with Judd Hirsch, Tony Shalhoub and Jason Biggs, who was also making his Broadway debut. Soon after his run on Broadway, Krumholtz co-starred in two feature films, Life With Mikey (1993) with Michael J. Fox and Addams Family Values (1993) with 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 as the sarcastic head elf Bernard from The Santa Clause (1994) and its first sequel The Santa Clause 2 (2002). However, because of his filming schedule on "Numb3rs", which conflicted with the filming schedule on the second sequel, he could not reprise the role of Bernard in The Santa Clause 3: The Escape Clause (2006).\n', '
In 1994, Krumholtz co-starred in his first television series, Monty, with Henry Winkler; the show lasted only a few episodes. Krumholtz later starred 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 Numbers. Along with his starring roles on television, Krumholtz made guest appearances on ER as schizophrenic patient Paul Sobriki, as well as on Law & Order, Undeclared, Lucky, and Freaks and Geeks.\n', '