Arnold lives in Chicago with his wife Janet, their kids, and their Tante Sarah. He has some knowledge of his brother's neighbors on Sesame Street, as he procures a jar of mud from Lake Michigan for Oscar the Grouch before he makes the trip.
Like his brother, Arnold worked in his father's candy store as a child, where he learned how to make an egg cream. To their disdain, they both remember how to make it using different methods. However, they each seem to recall the same rules for playing flipping cards, as they engage in a mildly heated competition while trying to teach the neighborhood kids how to play.