Born in 1977 in Normal, Illinois, Dunn moved to Saint Paul, Minnesota, with his mother, when he was a toddler.

While attending Saint Paul Central High School, he was involved in theater and joined an improv comedy group.

[3] He has also appeared in Parks and Recreation,[4] Nick Swardson's Pretend Time, Game Shop, Burning Love,[5] a small part on CollegeHumor's If Google Was a Guy and co-starred as Garrett McNeil in Superstore on NBC.

[7] He is an alumnus of the improvisational comedy group Boom Chicago and has performed and taught at the Upright Citizens Brigade Theatre since 1999.

[8] Dunn has received two Emmy Award nominations for Outstanding Writing for a Variety Series for his work on Key & Peele.