But when Ronnie O'Sullivan beat Scotsman Graeme Dott to become the Embassy World Snooker champion this week, his former deputy headteacher, Anne Abbott, had nothing but praise for her tearaway pupil.
Ms Abbott, who retired from the teaching profession two years ago, taught the new champion history during his time as a pupil at Wanstead high school in Redbridge, north-east London.
"I'm a huge fan - I've followed his career since he was a boy," said the 68-year-old.
"But if you're a top-class sportsman, it's going to affect your school attendance.
"He was winning championships at the age of 12. There was no question of concentrating on his schoolwork and putting snooker aside until later. We all realised that."
As well as excusing the extended absences necessary for her former pupil to attend matches and training sessions, Ms Abbott was also willing to accommodate the adolescent Ronnie's decision to pay his classmates to complete his homework for him.
"These were his coping strategies," she said. "And at least he paid for it.
It was a business transaction. He didn't bully anyone into it."
But Mr O'Sullivan has since admitted to mixing with rebel teenagers, and was renowned as a playground bully.
The champion has also acknowledged that he owes much to his former teachers.
Mr O'Sullivan told The TES that he has fond memories of Ian Townsend, the woodwork teacher with whom he crafted a case for his snooker cue.
He also admits to enduring memories of Ms Abbott, who receives a mention in the player's autobiography.
And the feeling is mutual.
"I have a soft spot for him," Ms Abbott admitted.
"I spent a lot of time counselling him when he was 16 and his father was sent to prison for murder.
"When you know someone, you don't stop caring about them. We knew at an early age that he had innate talent.
"I'm not going to make myself out to be a pie-eyed goody-goody, and I don't want to overstate my role. But it may have helped him get where he is."