Leighton Oosthuisen is from South Africa, and emigrated to the USA 25 years ago. Leighton started shooting competitively in 1997 in single stack, in the days of Combat Shooting. In 2016 he became a Grand Master, joking that it took ten years to progress from Master to GM.

He has placed top 10 in many Area Championships, and in 2017 won the Yuma Classic. In 2014 he represented the USA in the World Shoot, winning a Gold in the Senior Open Team division.
In 2017, he again represented the USA in France at the World Shoot, placing second in the team event.

Leighton works in the pet behavior field, and owns Partners Dog Training School in Arizona. He has two children, Christopher Oosthuisen, a well known GM shooter, and Alessandra.

Leighton is a proud member of the EMG Custom Team, and shoots an EMG .38 Supercomp pistol.