One of the best to ever do it! In the elite world of mixed martial arts (MMA), Kayla Harrison is truly in a league of her own. For starters, she is the only female Olympic gold medalist to win a title in the Ultimate Fighting Championship (UFC). Actually, make that a two-time gold medalist with judo victories in the Summer Olympics in London (2012) and Rio de Janeiro (2016). Raised on a steady diet of judo training by her black- belt mother from age 6, she not only earned a World Championship medal in the sport (2010) but also became the youngest American in history promoted to Rokudan (6th-degree black belt) status. Once she put her mind towards MMA fighting, there was no stopping Harrison: Her fast-paced fighting style earned her the belt as two-time Professional Fighters League (PFL) lightweight champion. The dominance continued upon signing to the UFC in 2024, storming up the ranks in record time to clinch the UFC Women's Bantamweight Championship in 2025. Already a multiple Hall of Fame inductee, including the United States Judo Federation HoF (2015) and International Sports HoF (2023), Harrison is far from done leaving her mark on combat sports. Keep following her milestone-heavy career and don't forget: Stepping into the Octagon against Kayla Harrison? Worst idea, ever!