Big Brother is a giant teenage villain based on the common archetype of the abusive older brother. He first appears in Operation: M.I.N.I.-G.O.L.F. where he is defeated by Numbuh 2. In Operation: M.O.V.I.E., he apprehends Numbuh 4 when his disguise is blown. In Operation: Z.E.R.O., his giant pants are on display in the KND museum.
Big Brother does not incorporate himself with the Teen Ninjas probably due to his size, and rather assembles with other adult villains if not working alone.
- Big Brother's name comes from George Orwell's book 1984, although he is completely different from the Big Brother in that story.
- This character may have been inspired by the villain Solomon Grundy from DC comics, but his appearance (Blonde short hair, red-stripped shirt, jeans and tan skin) bears a heavy resemblance to The Russian, villain from Marvel's Punisher comics.