Supercars chief executive James Warburton will stand down at the end of the season after four years in the role.
The former Ten Network boss did not give a reason for his departure, claiming he leaves the sport with increased crowd figures.
"With a heavy heart, I advise the 2017 season will be my last as CEO of the Supercars Championship," Warburton said in a statement on Monday.
"It is fair to say the sport is in great health. We have achieved so much with unity and, more importantly, the path is set to raise the sport to even greater heights.
"Every single metric from EBIT (earnings before interest and taxes), team distributions, crowd attendance to media numbers are well up and the fans continue to vote with their feet."
Warburton's efforts to widen the appeal of the Supercars included dropping reference to V8s in the championship's title to open the door to new manufacturers and different engine types.
He announced this month a long-planned night race in Sydney for the 2018 season, plus a new event at the $110 million Tailem Bend circuit in South Australia.
The season will end with the Newcastle 500 on November 26 ahead of races on the Gold Coast and Auckland.
