Known best for comedy acts that focus on his home state of Maine, Marley performed on David Letterman's and Conan O'Brien's late night talk shows, as well as on several Comedy Central programs. In addition, he played the role of Detective Greenly in the film The Boondock Saints and its 2009 sequel.
His early comedy albums include 3000 Shows Later, All New Stuff, and Up Against the Brick Wall.
In late 2010, he broke a Guinness World Record by performing a forty-hour-long stand-up comedy act.
He was born in Portland, Maine, to parents Robert and Marcia. He grew up in Bangor, Maine.
He appeared on The Martin Short Show.