Based on a true story. In December 1970, Elvis Presley met President Richard Nixon, who appointed Presley as an honorary DEA agent.
Portraying Elvis Presley, Michael Shannon thought that the karate scene in the film was over the top.
Essential to fleshing out the story were two first-hand accounts of the meeting and the events leading up to it. The memoir "Me and a Guy Named Elvis", by long-time Elvis Presley confidant Jerry Schilling, became a road map for the writers in early drafts. The handwritten notes taken during the meeting by Richard Nixon counsel Egil Bud Krogh, which he later compiled into his own account, "The Day Elvis Met Nixon", were incorporated into the final draft.
Elvis Presley and Jerry Schilling used to practice karate. They even had karate names: "Mr. Tiger" and "Mr. Cougar" respectively.