He is friendly but eccentric. He and Princess live in a Japanese-styled house. He has a weird obsession with crystals, and he likes to meditate during his free time. He has a very high opinion of his daughter, and it seems that he will pretty much do anything to show everybody how "great" she is.
Doctor Roberts is the drummer in Irving's band, "The Sillies."
Jeff Glenn Bennett replaces Matt Berry as the voice of Doctor Roberts since "Steamgate".