Along with Alec Berg and David Mandel, Jeff Schaffer was an editor on The Harvard Lampoon while attending Harvard University. After graduation, the trio worked as writers for Comedy Central's TV show MTV, Give Me Back My Life! Following that, Berg and Schaffer worked for Late Night with Conan O'Brien, then the trio reunited to work on the hit series Seinfeld, serving as executive producers as well as writers. Together, they made the switch to feature films with extensive rewrite work on a number of movies, including the hit comedy Dr. Seuss' How the Grinch Stole Christmas (2000). Their first screenplay was another film based on a book by the beloved children's author - Dr. Seuss' The Cat in the Hat (2003), starring Mike Myers.
Schaffer made his directing debut with the trio's second script, Eurotrip (2004), a comedy about four teenagers who experience culture shock on a European vacation.