[citation needed] He attended Redwood High School in Marin County, California, and Principia College in Illinois.

[1] He later attended University of California, Santa Barbara, where he received a Bachelor of Arts degree in music composition.

He played Harry Landers in the "Hospital" skit from Amazon Women on the Moon opposite wife Michelle Pfeiffer, whom he had previously directed in the ABC Afterschool Special One Too Many in 1985.

Horton also appeared in the 1997 TV movie version of the Jon Krakauer book Into Thin Air: Death on Everest, playing Scott Fischer, the leader of the disastrous 1996 climb on Mount Everest.

As a director he has worked on several television series including The Shield, Thirtysomething, The Wonder Years, Once and Again, and directed the pilot for Grey's Anatomy as well as pilots for Class of '96, Birdland, Dirty Sexy Money, The Philanthropist and Reconstruction.

Of their relationship, Pfeiffer reflected, "I broke one of my own Ten Commandments never to date an actor, especially one you study with.