Harvard lost last year when the race was restarted following the dunking of Waikato rower Richard Power. They were also the victims in 2007 when they were leading before a successful Waikato protest again saw the race restarted and Waikato powering away for victory.
There were no such problems on the Waikato River in 2015, with the powerful Harvard crew leading from start to finish with Cambridge University edging Waikato for second by 0.17 seconds.
Harvard became the first US crew to claim the Harry Mahon Trophy in what was Waikato's first loss in the main event since 2012.
For the first time the University of Waikato entered a novice crew in the corporate competition and after a long day of racing on Saturday they finished in 12th place out 17 teams. The team also won the corporate training video challenge, where crews made videos documenting the crews' training in the build-up to race day.
In the schools Head of the Waikato races, Hamilton Boys' High School made it three years in a row by defeating Sacred Heart Auckland while Diocesan School for Girls beat Epsom Girls in the girls section.