Willard Wallace was a little boy who kidnapped Monty Uno when he went on a fishing trip with his son in Operation: O.O.M.P.P.A.H.. Willard claims that his own dad has left him forever and intends to steal a new one. Numbuh 1 attempts to get his father back by challenging Willard to an Oom-pah playing competition, but is not very good. In the end, Willard's father, who had simply left a few minutes ago to get milk, returns to him and Numbuh 1's dad is let go.

He was a competitor at the Toobathon Race in Operation: C.A.K.E.D.-F.O.U.R., and was seen in line at Vaseball Stadium in Operation: B.R.E.A.K.U.P.. He was last seen trying to fish out The Great White Asparagus in Operation: I.N.T.E.R.V.I.E.W.S., and was then eaten by it.