Donald Jacob Hager Jr., better known as Jack Swagger and Jake Hager, is an American professional wrestler, former mixed martial artist, former amateur wrestler, and slap fighter. A standout amateur wrestler at the University of Oklahoma, he earned All-American honors in 2006 while setting the school record for most pins in a season before signing with World Wrestling Entertainment (WWE) later that year. During his WWE run, he became a former World Heavyweight Champion, ECW Champion, United States Champion, and Money in the Bank winner before leaving the company in 2017.

After WWE, Hager competed in Total Nonstop Action Wrestling (TNA), Lucha Underground, and Major League Wrestling (MLW) before joining All Elite Wrestling (AEW) in 2019, where he spent five years as a member of The Inner Circle and the Jericho Appreciation Society. Outside of wrestling, he compiled an undefeated 3-0 (1 NC) record in Bellator MMA before retiring from mixed martial arts in 2023, later making his Power Slap debut in 2026. He is also the final Lucha Underground Champion, was part of Pro Wrestling Illustrated's Faction of the Year in 2021 with The Inner Circle, and was ranked No. 18 in the PWI 500 in 2009.