Brother is a publicist.
Won Outer Critics Circle award for outstanding newcomer for his work on the New York stage-Arcadia and Bus Stop.
Attended University of North Carolina at Chapel Hill for undergraduate work.
Has a Master's in Fine Arts.
His parents divorced when Billy was in junior high school, and then remarried -- each other -- when he was in high school.
Grew up in Dallas, Texas, and has two brothers.
In 1998, he joined a theatre group called, "The Lab!" at UNC Chapel Hill and performed the role of 'Schroeder' in the musical "You're a Good Man Charlie Brown!".
While attending the University of North Carolina, he starred in a student-produced, university access-channel TV soap opera called General College.
Was in the "Boy Scouts of America" while growing up in Texas.
Loves to play golf, and often partners director Bart Freundlich.
He is able to turn down many jobs, because he makes millions of dollars each year using his voice to sell products as a 'voice over actor'.
Attended St. Thomas Aquinas HS in Ft. Lauderdale, Florida.
He was the second choice for the role of Russell in Almost Famous (2000). The first choice, Brad Pitt decided instead to appear in the more financially successful film Fight Club (1999).
Was "replaced" by actor Michael Hayden in the Lincoln Center Theatre production of "Henry IV". 
Declined an offer to play Bruce Banner in Hulk (2003).
Has a son, William Atticus (born January 7, 2004) with actress, Mary-Louise Parker.
Was nominated for Broadway's 2002 Tony Award as Best Actor (Play) for portraying the title character of John Merrick in a revival of "The Elephant Man."
Has been the voice of the acclaimed MasterCard "Priceless" commercials (airing in America) since 1997, but first appeared on-camera in one of these spots in 2005.
Graduated from University of North Carolina - Chapel Hill with a degree in Speech Communication.
In 2005, he was nominated for Best Actor in a Play at the Tony Awards for his part in Martin McDonagh's The Pillowman.
Nominated for the 1997 drama desk award for outstanding featured actor in a play for Anton Chekhov's "Three Sisters.".
Won the Theatre World Award for his role in Arcadia.
MFA in Acting - New York University, Tisch School of the Arts (1994).
Once worked as an historical interpreter at Roanoke Island Festival Park, in Manteo, NC.
In 2007, he won a Tony Award for Best Featured Actor in a Play for his performance in "The Coast of Utopia".
Though it is commonly mispronounced, his last name is actually pronounced, "croo-dup.".
He and his Watchmen (2009) co-star Jeffrey Dean Morgan both have been in pretty tumultuous relationships with Mary-Louise Parker. Crudup's and Parker's relationship ended when he left her to be with Claire Danes when Parker was seven months pregnant with Crudup's son. Morgan started dating Parker in 2007, they broke up in June the same year, then they got back together and became engaged, but eventually broke up for good in 2008.
Currently filming with Johnny Depp, Christian Bale, Marion Cotillard in Michael Mann's movie, Public Enemies (2009). [June 2008]
In Off-Broadway production of "The Resistible Rise of Arturo Ui" 
On Broadway playing "Vissarion Belinsky" in Tom Stoppard's "Coast of Utopia" trilogy. [December 2006]
Performing on Broadway with Jeff Goldblum in "The Pillowman". [April 2005]
Starring in the Broadway production of Martin McDonagh's hit play, "Pillowman", also starring Jeff Goldblum. [March 2005]
He has English, German, and Scottish ancestry.