After Jim's first appearance on The Late Show with David Letterman, Mr. Letterman personally chose Jim to develop a sitcom for World Wide Pants. A year and half later, Welcome to New York debuted to critical acclaim boasting a cast of Christine Baranski, Rocky Carroll and Sara Gilbert. The Wall Street Journal declared Jim "a true find" and TV Guide Nominated Jim for Best New Actor in a Sitcom TV Guide Award.

Jim has guest starred on many other network television shows including Law & Order, Third Watch, Ed, That 70's Show, Lateline, Law and Order: Special Victims Unit, Soul Man and Conrad Bloom. Jim was also a cast member of the VH1 sketch show Random Play. Some of his other film credits include Three Kings, Road Trip, Endsville, Personals and Entropy. Jim also appeared in two films chosen for the 2001 Sundance Film Festival Super Troopers and Thirty Years to Life.

Some recognize Jim from his numerous commercial campaigns, which include ESPN, Saturn and Rolling Rock. Jim's commercial presence was a so large and successful in 1999 Business Week called him "Salesman of The Year".

As a stand up comedian, Jim's cutting edge style has earned him 9 unprecedented appearances on Late Show with David Letterman. Jim has also numerous appearances on Late Night with Conan O'Brien, The Late Late Show with Craig Kilborn and Comedy Central's Dr. Katz. Jim performed is own half hour comedy special for comedy central entitled Comedy Central Presents: Jim Gaffigan. Jim has performed at both the prestigious HBO US Comedy Arts Festival in Aspen, Colorado and the world renowned Just For Laughs International Comedy Festival in Montreal, Canada.