Horn served in various positions at 20th Century Fox and at Norman Lear’s television production companies, Tandem Productions and Embassy Communications. He was also one of the founders of Castle Rock Entertainment, now a subsidiary of Warner Bros. There, he oversaw films including A Few Good Men, The Green Mile, When Harry Met Sally, and the TV sitcom Seinfeld. Horn became President and COO of Warner Bros. in 1999, where he ran the studio in partnership with Chairman and CEO Barry Meyer for 12 years. Under Horn’s leadership, Warner Bros. had many hits, including the Harry Potter series and Christopher Nolan’s The Dark Knight Trilogy. He was also the executive producer of The Hobbit: An Unexpected Journey.
A passionate environmental advocate, Horn is chair of the Natural Resources Defense Council. He is a member of the Academy of Motion Picture Arts and Sciences, the Academy of Television Arts and Sciences, and he serves on the American Film Institute Board of Directors and the Harvard Business School Board of Dean’s Advisors. He is the recipient of the Will Rogers Motion Picture Pioneers Foundation’s 2004 Pioneer of the Year Award, Harvard Business School’s 2007 Leadership Award and 2016 Alumni Achievement Award, the Producers Guild of America’s 2008 Milestone Award and the Geffen Playhouse’s 2014 Distinction in Service Award.
Horn earned his MBA from Harvard Business School and served as a captain in the U.S. Air Force. In 2010, he received an honorary Doctor of Fine Arts degree from New York’s Union College, his alma mater.