[2] Harper played as a right-handed batsman in Adelaide grade cricket competition for the Teachers' College and East Torrens clubs.

Harper umpired the opening match of the 2003 Cricket World Cup in South Africa, and went on to stand in one of the semi-finals.

[3] In 2010, England lodged a formal complaint against Harper after a referred caught behind decision was turned down because the volume supplied by the home broadcaster was not good enough to detect the edge.

Harper retired from umpiring following some heavy criticism from India during the first test against the West Indies.

[9] Dave Richardson, the ICC Cricket manager, said Harper received "unfair criticism" from the Indian players and that his correct decision making percentage against India was at 96 percent, which was "considerably above average".