Morrison began playing junior football for the Terrigal Sharks in the Central Coast Rugby League.

In 2005, Morrison was part of the Parramatta side which won the minor premiership but lost 29–0 in the preliminary final against North Queensland.

[citation needed] After three years with the Bradford Bulls, Morrison signed with the Wakefield Trinity Wildcats for the 2010 season.

He was promoted to the interchange bench after Warrington centre Matt King dropped out for personal reasons, and played for a large part of the game.

[9] On 11 November 2011, Morrison announced his immediate retirement from the game, acting on advice from health professionals, due to a serious shoulder injury.

Following his charity run out; Glenn signed for Salem to play through the 2019 winter season, debuting at fly half in the opening preseason game against Yarnbury XV.

On 5 September 2012, it was announced Morrison was leaving Wakefield to take up the position of head coach for two years at the Dewsbury Rams.

[12] After a run of defeats during the early stages of the 2017 championship season, Morrison announced he would be stepping down as head coach at Dewsbury Rams on 27 March after a near five-year tenure .