Harrison Henry Max is an American boy who was formerly the commissioner of the School Safety Patrol at Gallagher Elementary. He looked at the KND in disgust and at Numbuh 2 for the leaving the force to join Numbuh 1.
In Operation: P.I.N.K.E.Y.E., Joe Balooka 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, Max discharged Joe from the Hall Squad for his corruption.
Sometime later, Max was removed from the force since the Delightful Children From Down The Lane bribed President Jimmy Nixon McGarner to become the new commissioners. Loeb was outraged by this in in Operation: C.R.I.M.E.
Max later joined the Kids Next Door since he had enough of the School Safety Patrol's corruption and got accepted due to his experience in ninja training and since he does karate in his spare time. Max got a code name called Numbuh 456, 227. Max seeks to deal with the corruption at the school safety patrol once he saw that the KND's methods can help kids.
- His skin is similar to Ed from Ed, Edd, N' Eddy. It may be possible that he and Ed are cousins.
- He has ninja training.
- He does karate in his spare time.
- He and Knight Brace met before.