Attended Chatsworth High School with Kevin Spacey and Mare Winningham; Winningham and Kilmer dated during their teens
Started acting in commercials at age 12, and at 17, was one of the youngest students ever accepted to Juilliard's drama school
Made his Broadway debut in a 1983 production of John Byrne's The Slab Boys with Sean Penn and Kevin Bacon
Did his own singing when he played Jim Morrison in Oliver Stone's The Doors (1991)
Voiced KITT in NBC's 2008 Knight Rider reboot
Enjoys being outdoors; goes fishing, hiking and horseback riding in his spare time
In 2010, appeared in character as Mark Twain at Boston's Mary Baker Eddy Library, in connection with Kilmer's work on a film on the life of Eddy, who founded Christian Science, and Eddy's link to Twain
His appearance drew the library's largest crowd up to that time