John Kerr, the chief executive of England's second-largest exam board, has left the company by mutual agreement weeks before this year's exam season begins.
Mr Kerr, widely credited with having turned Edexcel around after taking over when the board faced a crisis in 2001, took an undisclosed redundancy payment last month. As he took over, the board had been criticised for a string of exam mistakes. It also faces a large deficit.
Stephen Mullarkey, previously finance director at Edexcel, has also left.
Edexcel said Mr Kerr was leaving to pursue "a number of entrepreneurial opportunities in the education field".
A spokeswoman said the moves had been timed to coincide with a restructuring by Pearson, the exam board's owners.
Pearson, the publisher of the Financial Times, controversially acquired a 75 per cent stake in Edexcel in 2003, making it the first major privatised exam board. Last month, it bought the other 25 per cent from the Edexcel Foundation, a charity.
Mr Kerr, who earned pound;219,000 in pay, pensions and bonuses in 2003, was responsible for supervising millions of exam entries every year. He did not respond to attempts by The TES to contact him.