Dumb John Silver was the helmsman of the Sweet Revenge in Operation: T.R.I.C.K.Y.. Sensitive, he was dressed up as a pirate for Halloween even though he was a real pirate. After being yelled at by Stickybeard many times, he quit, which allowed Numbuh 4 to take over the ship as the wheel wasn't being guarded by any of the other pirates. Dumb John Silver is assumingly his name, as Stickybeard called him this when yelling at him. He left Stickybeard's crew, but later popped up in Stickybeard's Armada and as one of the many victims of Grandfather in Operation: Z.E.R.O.
He was last seen in Operation: G.I.R.L.F.R.I.E.N.D., driving the Sweet Revenge when Stickybeard tried to steal the Sweater of Sweetness. His name is a parody of Long John Silver.
- His name is a parody of Long John Silver, a character in the book Treasure Island.
- Along with the Toiletnator, he is portrayed as one of the least villainous antagonists that the KND have faced.