He was named Fighter of the Year in 2004 by The Ring and the Boxing Writers Association of America for his upset knockout victory over Roy Jones Jr.

Glen "The Road Warrior" Johnson was a late bloomer of the sport, starting at 20 years old in Miami, Florida, at an emerging police boxing gym.

He journeyed to England and suffered a controversial draw against Clinton Woods, but defeated him in a rematch by unanimous decision to win the IBF light heavyweight title.

His next fight came against former undisputed light heavyweight champion Roy Jones Jr., who entered following an upset loss to Antonio Tarver earlier that year.

[1] On August 7, 2010, Johnson challenged Tavoris Cloud for the IBF light heavyweight title but lost a close decision 116–112 from all 3 judges despite landing more punches according to CompuBox.