Sean Gunn, the brother of Guardians director James Gunn, and the man who plays the role of Kraglin, plays Rocket on the set in a green screen body suit while in a permanent crouch.
Bradley Cooper is the actor most associated with Guardians of the Galaxy’s Rocket, by virtue of the fact that he provides the character’s voice.
However, it’s another actor who actually does a lot of the work to bring Rocket to life.