The 2001 world champion converted at the Islamic Cultural Centre in Regent's Park in London last month, according to his mother.
"Ronnie is a lot better in himself since he converted. I hope it will steady him," she said a British newspaper this Sunday.
Maria O’Sullivan confirmed that former world featherweight boxing champion Prince Nasim Hamid had been influential in his conversion.
The boxer had introduced him to an American, Khalid Yasin, a high-profile Muslim preacher who is involved with others in trying to set up an Islamic satellite television station in Britain.
As a boy prodigy, O'Sullivan did not seem to have a care in the world. His ability was phenomenonal – equally comfortable playing right or left-handed.
"When Ronnie's on song, everybody else looks like a cart horse," said six-times world champion Steve Davis.
But despite his international success, O’Sullivan’s family life has been troubled - his father began a life sentence for murder in 1991.
The enforced separation led to a depression from which the snooker player has rarely found relief.
History of depression
The 27 year-old derived some initial benefit from psychotherapy but stopped as his impatience grew for quicker results.
Depressed on the eve of the 2001 world championship he turned to Prozac which, he admitted, alleviated his anxieties and promoted the ideal state of mind which helped him take the world title.
Early this year, O'Sullivan won two tournaments back to back but lost his opening match at the Crucible to Marco Fu and declined invitations to play in lucrative events in Hong Kong and Bangkok in August.
His first appearance of the season will be in the LG Cup, which starts at Preston, England, next Saturday.