Mr. Apatow was born on December 6, 1967 in Syosset, New York to a Jewish family and is a successful American screenwriter, director, and producer most known for a series hilarious films including The 40-Year-Old Virgin, Knocked Up, and Superbad and is the founder of Apatow Productions which also produced the short-lived television shows Freaks and Geeks and Undeclared. In addition to Apatow, the aforementioned films have writers and actors in common including Seth Rogen (writing, producing, and acting) and Jonah Hill (just acting), much like the Kevin Smith "View Askew" or "View Askewniverse" films of the 1990s.
Judd's parents divorced when he was 12 and he actually ended up living with his father (brother Robert ended up with the grandparents and his sister Mia stayed with the mother). His hero was Steve Martin and, like the inimitable comedic star, he really got his start with stand-up comedy at age 17 when he was a senior in high school. Apatow enrolled in the screenwriting program at University of Southern California but dropped out after two years and moved into an apartment with none other than Adam Sandler.
Like Sandler, Apatow could write funny material, but unlike the wacky Sandler, lacked the performance skills to round the act out. Thus he began writing jokes for other who did have an abundance of that talent, like Roseanne Barr for instance, and so he realized his destiny to be a comedic writer. Apatow's agent hooked him up with Garry Shandling and this got him a gig writing for The Larry Sanders Show in 1993. This earned him no less than six Emmy nominations.
And he also rewrote Lou Holtz' script for the The Cable Guy. Oh well, can't win 'em all (I wonder how bad the first one was). At least that's where he met his future wife, actress Leslie Mann (who has appeared in both The 40-Year-Old Virgin and Knocked Up). However it was the small screen again, with Freaks and Geeks and Undeclared that really led to his breakthrough in 2004 when he got to be a producer for Anchorman: The Legend of Ron Burgundy. This likely paved the way for the successful series of movies he is knee-deep in now.
Judd Apatow and Leslie Mann have two daughters, Maude and Iris. Both girls appeared in Knocked Up as well. They all live in Los Angeles, California.
I do not cover all of the projects he's been involved in here, just the notable ones.
Sources: Wikipedia, IMDB.com