Whilst pursuing his bachelors' degree at the University of Pretoria, Heinrich Klaasen gained an interest in cricket after he made it to his college team. Rising through the ranks, he was handed a first-class debut for the Northerns in the 2012/13 season. Having taken the longer route to the top through domestic cricket rather than age-level cricket, Klaasen piled on the numbers and had an exponentially rising graph in his first three seasons, starting off with an average of 42 in his debut season which inflated to an exemplary 65 in his third.