His name and profession are an inside joke, as the word mort is Latin and French for the word death, which is central to his job as a funeral director or "mortician." It could also be short for Mortimer, which Louise calls him in one scene in "Tinarannosaurus Wrecks."
Despite his reduced appearances, he has remained one of the few non-main characters to appear in every season as well as the film.
His participation in an episode is often very brief. He may have no more than a sentence or two, and his part frequently has no dialogue. For example, in "Synchronized Swimming," his entire screen time consists of sitting at the counter and telling Bob that his burger is burning. In "Food Truckin'," he prevents Teddy from throwing a brick through the restaurant's window in a dialogue-free scene, and in "Moody Foodie," he is part of the group reading the restaurant's review and also part of the group watching the movie Tin Cup near the end of the episode. There's also a running gag where he enters the restaurant, sees whatever chaotic thing is occurring, and then changes his mind about eating/visiting and leaving.
He is a subscriber to Prominent Professors, a website with video classes taught by professionals. His username is "Thethundertaker" and his password is "urnthis." ("Three Girls and a Little Wharfy")
