The actor and producer will play the boss of Brad (Damon Wayans Jr) in an early episode of the ABC sitcom's new run, according to New York Magazine.
Wilmore has only been hired for a single episode, but his character could recur later in the new season.
In addition to his writing and producing duties on such shows as The Office and Love Bites, Wilmore has been a frequent contributor to The Daily Show since 2006.
He has also appeared in episodes of How I Met Your Mother and Accidentally on Purpose. Earlier this year, he signed up to appear in a CBS comedy pilot, though the project was ultimately not picked up to series.
Other actors confirmed to appear in future episodes of Happy Endings include The Secret Life of the American Teenager star Megan Park, Make It or Break It's Nicole Gale Anderson and Hall Pass actor Derek Waters.
The comedy returns to ABC on September 28 at 9.30/8.30c, while the first season airs in the UK on E4 from Thursday at 9pm.
> Elisha Cuthbert teases Happy Endings romance
Watch a clip from Happy Endings below: