After graduating from University of Wisconsin–Madison in 1989, Dahm became one of the first writers for the satirical news site The Onion.

[1][2] Dahm was co-executive producer and head writer for The Colbert Report from 2005 to 2013, helping launch the series from its earliest days as a spinoff of The Daily Show.

and America Again: Re-Becoming the Greatness We Never Weren't,[3] the live Rally to Restore Sanity and/or Fear on the National Mall in Washington, D.C., A Colbert Christmas: The Greatest Gift of All!, and the 2006 White House Correspondents' Dinner.

[4] He has stated that his favorite moment on the show was Colbert's mock feud with indie rock group the Decemberists which culminated in a guitar solo competition on the show's final episode of the year, featuring guest appearances from guitarist Peter Frampton and Dr. Henry Kissinger.

[7][8] Dahm has won six Emmy Awards: Four in the category of Outstanding Writing for a Variety Series four times for The Colbert Report in 2008, 2010, 2013, and 2014, and shared the show's awards for Outstanding Variety Series in 2013 and 2014 as co-executive producer.