Mortensen spent his formative years in Green Bay, Wisconsin. He graduated from the University of Wisconsin–Green Bay in 2001 and spent time working with his father at the family-owned Jones Sign Nationwide, where he gained an appreciation of his ability to make others laugh.
While he has said his job at Jones Sign was "incredible," he regarded his position with unease, feeling it based on nepotism. Eager to see if his own talents could net him recognition, he began performing comedy in 2004 on a visit to Madison, Wisconsin. Within a year he had collaborated on a group for young stand up comedians called the WiSUC Project, short for "Wisconsin Stand-Up Comedy Project", and won their first ever comedy contest. In 2007 Mortensen moved to Madison.
Mortensen moved through the traditional ranks of stand-up comedy with curious velocity. While many comedians linger in the house emcee or middle for years, Mortensen headlined the Majestic Theater in Madison 2008, just months after opening at the same venue for comedian Christian Finnegan.
Nick ran into some trouble in June 2007 with the Madison Comedy Club as the result of a front-page article in Madison's The Capital Times where he was quoted as saying "The club here (in Madison, WI) is super cool and a pleasure to work at, but generally speaking, comedy clubs are where comedians and comedy itself goes to die." . The Madison Comedy Club subsequently canceled his future bookings with the club and erased his profile from the comedians section on their website. Nick was said to be unsurprised and has stated on his blog on occasion that comedy clubs often resort to punitive measures to keep comedians in line. He's further stated that it is not of tremendous importance for him to work in clubs because he prefers colleges and rock and roll clubs and sees comedy clubs as one of many different means of display while comedy clubs often see themselves as means of production.
In August 2007, the experience with the Madison Comedy Club became a turning point for Nick. He decided he would no longer work in comedy clubs, instead choosing to focus on the college and corporate circuits and the Internet. One of his big issues with comedy clubs, he stated, was that they made the comedian into a glorified alcohol salesman and he no longer wanted to be a part of the alcohol paradigm, citing the fact that he'd tended bar and had seen the damage that alcohol does to the lives of those who abuse it.
- Rozwadowski, Tom (December 18, 2005). "Taking Comedy Out of the Clubs". Green Bay Press-Gazette, Section D (Life)p. 1-2.
- Comp, Nathan J. (June 8, 2006). "[Home Grown Comedy Tickles Madison] ".
- The Capital Times