Submitted Paul Buentello by strikes in the 2nd round on November 16, 2007 to become Strikeforce's first heavyweight champion. The event was "Strikeforce: Four Men Enter, One Man Survives". (November 2007)
Knocked out Todd Duffee at "K-1 Dynamite!! Power of Courage 2010" in 19 seconds to become interim Dream heavyweight champion. (December 2010)
Became the only fighter in the world to hold the K-1 kick-boxing Grand Prix heavyweight title and the Strikeforce mixed martial arts heavyweight title. (December 2010)
In the K-1 World Grand Prix tournament, Overeem defeated Tyrone Spong, Gokhan Saki, and Peter Aerts to win the K-1 World Grand Prix Championship. (December 2010)
Made combat sports history by defeating Peter Aerts to become the K-1 World Grand Prix tournament champion. (December 2010)
Made combat sports history by defeating Peter Aerts to become the K-1 Grand Prix tournament champion. (December 2010)
Released from his UFC contract on the same date as Junior Dos Santos. The date was March 3, 2021.