Born in Portland, Maine to attorney Leonard Nelson and his wife, Merle Nelson, (attorney and state assemblywoman), Judd attended St. Paul's preparatory school in Concord, New Hampshire before majoring in philosophy at the prestigious Haverford College in Pennsylvania. The acting bug bit when he went to watch a friend's audition and was obliged to audition in order to stay. He won the role.

After graduation, Judd headed for New York City and the Stella Adler Conservatory where he was believable in the role as the "street-smart Eddie Keaton" in the comedy The Last American Preppy. Judd's next film role was as the stodgy ROTCer, Phil Hicks, in the ensemble comedy Fandango. Important and diverse roles in the brat-pack films The Breakfast Club and St. Elmo's Fire quickly followed. With his privileged upbringing, Judd could have brought the right degree of preppy-smarmyness, (ala James Spader), to any number of vapid roles, but his intense stare and dark smoldering looks gave him a hint of danger which added to his credibility in films like the Billionaire Boys Club, From the Hip and New Jack City.

While Judd's career has been peppered with under-promoted films and poorly-written TV appearances, critics have not been overly kind to this misunderstood actor.
Graduated from the prestigious Haverford College in Pennsylvania. He appeared in John Parr's "St. Elmo's Fire (Man In Motion)" music video. Was one of the nine original members of the 1980s "brat pack", along with Andrew McCarthy, Mare Winningham, Anthony Michael Hall, Demi Moore, Rob Lowe, Molly Ringwald, Emilio Estevez and Ally Sheedy Was once engaged to Shannen Doherty. When he left Suddenly Susan, he was replaced by his The Transformers: The Movie castmate Eric Idle. Currently resides in Los Angeles. [2006] Favorite baseball team is the Boston Red Sox. Has a Staffordshire Bull Terrier named Talluah Bighead. Has two younger sisters, Eve and Julie. His manager is Steven Siebert. Loves to play golf, read and ride his motorbike. Loves to write.