As a writer, Koepp worked on blockbuster Hollywood films such as Jurassic Park, ', and Spider-Man. He had a cameo appearance as the "Unlucky Bastard", a minor character devoured by a T. rex roaming San Diego in ', which he co-wrote and was second unit director of. Although Koepp did not write Jurassic Park III, he did devise the film's basic storyline. Koepp later declined an offer to write a script for the series' fourth film, Jurassic World, as he felt he had nothing left to contribute to the series. Koepp was reportedly paid $4,000,000 for his Panic Room screenplay. He wrote the screenplay for Indiana Jones and the Kingdom of the Crystal Skull and co-wrote and directed 2008's Ghost Town starring Ricky Gervais and Greg Kinnear. Koepp's work as a director has not had quite the same box office success. His films include Secret Window, Stir of Echoes, and The Trigger Effect. Koepp has also worked in television, creating the 2002 series Hack starring David Morse. In 2012, Koepp directed Premium Rush, which he co-wrote with John Kamps. In an August 2011 lawsuit, Joe Quirk, the author of the 1998 novel The Ultimate Rush, accused Koepp and the makers of Premium Rush of copyright infringement. On April 2, 2013, U.S. District Judge Richard Seeborg dismissed this case, finding that the two works were not substantially similar. On February 17, 2013, Koepp received the WGA East's Ian McClellan Hunter Award for Career Achievement. On July 10, 2013, Lionsgate was reported to have acquired the comedic crime novel The Great Mortdecai Moustache Mystery, written by Kyril Bonfiglioli. Koepp directed the film, titled Mortdecai, from a script by Eric Aronson; Johnny Depp played the lead role of Charlie Mortdecai, and the film also featured Gwyneth Paltrow, Ewan McGregor, and Paul Bettany. Koepp adapted the Marcus Sakey novel Brilliance, which will star Will Smith and Noomi Rapace. On March 15, 2016, The Walt Disney Company announced a fifth installment of the Indiana Jones saga, with Koepp as its screenwriter. By June 2018, Koepp ultimately backed out of the project due to his commitment to You Should Have Left, a film Koepp wrote and is set to direct. which is based upon novel of the same name by Daniel Kehlmann, which will star Kevin Bacon and Amanda Seyfried. On September 3 of 2019, Koepp made his novel debut with the release of the book Cold Storage, a science-fiction thriller.
