Oleksandr Oleksandrovych Usyk is a Ukrainian professional boxer. He was the undisputed world heavyweight champion twice in 2024 and 2025 and held the unified heavyweight championship from 2021 until vacating his sanctioning body titles in June 2026, and has held The Ring heavyweight title since 2022. He held the undisputed championship in two weight classes—cruiserweight and heavyweight—and is the first male boxer to become a three-time undisputed champion in the "four-belt era". Undefeated at the time of relinquishing his belts, Usyk is still considered to be lineal heavyweight champion of the world. World heavyweight champion (WBA (Super), IBF, WBO) from September 25, 2021 to May 18, 2024. Wiki link