Mr. Stevenson is Krusty the Clown's agent.
When Krusty got fired, he went to Mr. Stevenson for help. He left Krusty as a friend and a client. Krusty mentions that they shared boats, condos and girlfriends and when he finished each one of them was spick and span.(The Ten-Per-Cent Solution)
He shows Krusty various international versions of him. When they run from them, he asks Krusty why he ever became a clown. Krusty responds saying he was originally going to be a sad one.