In 1996, Derksen turned
professional. He began his professional career on the
Asian Tour in 1997. At the end of the year, he returned to Europe and earned his
European Tour card for the 1998 season via
qualifying school. He initially struggled to maintain his place on the main tour and has returned to qualifying school on five occasions. He has not always been successful in regaining his card, dropping down to the second tier
Challenge Tour twice, where he finished 8th on the end of season rankings in 2001. His first win on the European Tour came in 2003 at the prestigious
Dubai Desert Classic. His only other title to date was the 2005
Madeira Island Open Caixa Geral de Depositos, a European and Challenge tour dual ranking event. His best year-end ranking on the
Order of Merit has been 36th in 2007. In 2014 he said that he planned to retire at the end of the season. ==Amateur wins (5)==