Born and raised in Las Vegas, Nevada, Mir began training and competing in American Kenpo at a school owned by his parents, earning his black belt as a teenager. Mir’s father was a Cuban-born wrestler of Moroccan and Russian heritage, who played a major role in convincing him to begin wrestling on the basis that it could help him avoid submissions. Mir joined the wrestling team at Bonanza High School during his junior year and lost his first nine matches. During his senior year (1998) he went 44–1 and won the state championship. Mir played fullback and defensive end on the school’s American football team, which reached the Southern Zone semifinals in 1997. He also competed in track and field; his discus throw of 177 feet, 10 inches (54. 20 meters) is still a Sunset Regional record.