Heggemsnes has been training with his current coach Valentyn Skrypin since age 11. He made his international debut at the 2016 Junior European Championships in Bern, Switzerland, placing 42nd in the all-around during qualifications. Later that year, he competed at the 2016 Northern European Championships in Trondheim, where he was part of the gold medal-winning Norwegian team. Individually, he took the silver medal in the all-around and on the pommel horse, and the bronze on the parallel bars.