Dean Testerman is an actor and plays Steven's dad, a character in the Alternative Lifestyle series of videos. He first appeared in the video "I hate my dad and so should you." He is currently in a relationship with Toi.
In "I hate my dad and so should you." Steven is a little hesitant to meet with him. Steven says that he is his only son, but Dean plays it off otherwise making it seem like he has more children. Dean also tells Steven in the same episode that he and Steven's mom are getting a divorce, much to Steven's surprise. He then lead Steven (and the audience) on to believe that he wanted to "bond" with Steven over his fiancée Alyssa. He says that Steven had a lot of make-believe girlfriends growing up, and doesn't actually believe Alyssa exists. After they converse more, he finally admits that he has an older brother who lived elsewhere and "had" a younger brother at one point too. He offers Steven the chance to move in with him and meet his alive and dead brothers, but Steven declines.