Action Dexter is Dexter's Future Self as an adult. He has big muscles and can fight like a man. He is pure epic. He can operate and control weaponry which he uses to fight evil in the dark future where Overlord Mandark rules over the world.
Action Dexter is a big muscular man who has an orange beard and glasses. He wears a black shirt and a white ripped lab coat. It's revealed he has gone bald and that Old Man Dexter was actually wearing a wig.
- He still has Dexter's accent.
- He is the only one of Dexter's future selves that has not been seen in any other episodes besides Ego Trip.
- He and Action Hank have many similarities and traits.
- Action Dexter, unlike the other Dexters, was not voiced by Christine Cavanaugh. He was voiced by Jeff Bennett instead.