De Graaf reached the quarter-finals representing Sweden, alongside Oskar Lukasiak, at the 2024 PDC World Cup of Darts, after a five-year naturalisation period.

De Graaf managed to qualify for the 2013 BDO World Championship, where he faced compatriot Jan Dekker in the first round.

He reached the final of the BDO World Trophy in February, in which he played against Geert De Vos.

[7] In late March, De Graaf also made his debut on the European Tour at the German Darts Masters.

[8] A consistent debut year in the PDC saw him qualify for the Players Championship Finals and he overcame Steve Beaton 6–4, before being eliminated 6–1 by Robbie Green in the second round, despite averaging 101.22.

[9] De Graaf won a place in the 2017 World Championship through the European Order of Merit and he lost 3–1 to Jelle Klaasen in the first round.

In 2023, he started to represent Sweden instead of Netherlands, and made his debut at PDC Nordic and Baltic Tour.

[21] By reaching the fourth round in the World Championship, De Graaf made it into the top 64 on the Order of Merit, in the first year of his tour card.