Jerry Jarvis is to leave his job as head of Edexcel, one of England's big three exam boards.
He had been managing director at the privately owned exam provider since 2005.
After joining as operations director in 2000 he helped Edexcel recover from an embarrassing period when its mistakes were regularly making national news.
Mr Jarvis oversaw the introduction of technology that helped the board offer a more efficient service.
But he attracted controversy this summer when said that A-levels might need to be recalibrated.
Mr Jarvis said he was "ready to move on to the next phase of my career". He will be replaced in January by Ziggy Liaquat, currently Edexcel's operational manager.