Won a number of amateur titles, including the Valderrama Boys Invitational and Italian International Under-16s Championship in 2013. Represented Norway at the European Young Masters, Boys’ Team Championship and Amateur Team Championship.

Represented Europe at the Junior Ryder Cup, Bonallack Trophy, Eisenhower Trophy and Jacques Léglise Trophy.

In 2017, Signed a letter of intent to play college golf for the University of Texas, but decided instead to focus on his transition into professional golf.

Was still an amateur when. In 2018, he became the first Norwegian to compete at the U.S. Open after earning a place through Final Qualifying at Walton Heath.

Turned pro after earning a DP World Tour card through Qualifying School in 2018, going through all three stages, but was unable to maintain his status after his rookie season.

Secured his eventual return to the DP World Tour in 2024 after finishing seventh on the Road to Mallorca Rankings, ending the year with his first professional victory at the Rolex Challenge Tour Grand Final.

Won his first DP World Tour title at the 2025 Soudal Open. Teeing off three and a half hours before the leaders, he carded a nine under par 62 which forced a play-off against Ewen Ferguson and Darius van Driel. Reitan won on the second extra hole, becoming the second Norwegian to win on the DP World Tour.