Geoffrey St. John was the leader of the Kingdom of Acorn's Royal Secret Service. Following the organization's destruction at the hands of Dr. Ivo Robotnik, Geoffrey reestablished it in honor of his father, Ian St. John, who was also his predecessor. Following Robotnik's military coup, he gathered the few remaining members of the old Secret Service and formed them into the Rebel Underground, an organization originally proposed to King Maximillian Acorn but never put into action. After some time working independently, his group met the Knothole Freedom Fighters, and after a number of meetings began working together with them. Geoffrey served the Kingdom and later the Republic of Acorn loyally, but eventually revealed that he recognized Ixis Naugus as the rightful monarch, having served as his apprentice for years. He ended up having his body taken over by the corrupted king when he attempted to defect from his position.

Posess a strong cockney accent.