Mr. Stevenson Is Stewart's father and is a middle-aged man who is quick to anger. In early episodes, he is a teacher at Highland High (No Laughing, Citizen Butt-Head ). Later he is a businessman, judging from his cell phone and references to "the office" (Prank Call). He is a regular victim of Beavis and Butt-head's destructive shenanigans, such as having his house blown up (Stewart's House) or vandalized (Stewart Moves Away & Doomsday), being involved in a car accident by following wrong traffic directions (Blackout!), or having his own phone forcefully inserted into his rectum (Prank Call) when Beavis and Butt-head accidentally lead prank-call victim Harry Sachz to his house. He tries to come off as a caring and responsible family man, but he reveals his cowardly nature in times of distress, invariably trying to shift blame to Stewart. He has a large collection of pornographic magazines, which Beavis and Butt-head know the exact location of; along with this and the implication that he is impotent in Sperm Bank when he visits a sperm bank with his wife, he is either or not sexually attracted to his wife.
Just like Principal McVicker and Coach Bradley Buzzcut, he hates Beavis and Butt-Head (most notably in Sperm Bank, where he attempts to attack them). However unlike those two, there's times where he's been nice to the boys. This probably indicates he doesn't have a blind hatred of them like everyone else and only gets angry when they screw things up.