Shares in the company, which has been recovering from a tough year, fell as much as 2.7 per cent in early morning trading yesterday, before closing down 1.6 per cent.
Karpathios, who was chief executive of the group’s wholesale and international divisions and holds a 14.8 per cent stake, will step down from the board immediately.
A spokesperson denied that there had been any conflict with the group’s main founder Julian Dunkerton, saying he departed on good terms.
Karpathios said: “As a co-founder of the business, I will always take a close interest in SuperGroup and I look forward to its continued growth and success.”
Before joining SuperGroup, Karpathios built up his own skateboarding and clothing chain Skate of Mind, which he sold off in 2004.