Joe was secretly hired by the evil and certifiably insane Nurse Claiborne to infect kids with Pinkeye in exchange for her delicious crumbles (which turned out to be made from Pinkeye crust). When Numbuh 2 started investigating the epidemic and suspected Joe, Joe was shot before he could reveal any information. Later, he saved Numbuh 2 from Nurse Claiborne, being shot again and badly injured in the process. After this incident, Joe was fired from the Hall Squad for his corrupt activities, and afterwards worked at a store owned by his father as a parking attendant.
Numbuh 2 visited Joe's dad's store to get chocolate sauce for the Sanban Family, and Joe briefly suspected him of stealing the sauce before he found the money Numbuh 2 left on the checkout counter.
Sometime later, after striking a deal with a nerdy safety patrol member - known as Crayon Boy - Joe was reinstated into the Hall Monitor force, as seen in this episode.
- His name is a pun on the comic strip character Joe Palooka.
- He may have feelings for Numbuh 3 because when she (pretending) said, " I should have never fallen in love with you!", in Operation: C.R.I.M.E., his eyes got big and he almost got emotional.
- During his first appearance in Operation: P.I.N.K.E.Y.E. he and Numbuh 2 shared a fondness for Nurse Claiborne's crumbles (until they found out what the topping was); then he switched over to lollipops in S.P.A.N.K.E.N.S.T.I.N.E. and C.R.I.M.E. The lollipop is a reference to the habitual usage that cigarettes were in old detective movies, changed here for a more kid-friendly approach.
- His hair grows longer in each episode he appears in.