The victory over Judd Trump at Sheffield's Crucible theatre was particularly emotional for 'The Rocket' owing to the presence of his dad, who was there to share in the elation. But that has not always been the case.
Ronnie Jr burst into tears after potting the final ball to claim victory by 18 frames to 13. Afterwards, in an emotional interview with Eurosport, he opened up, describing the anguish of his dad missing his first world title win back in 2001 as he served a prison sentence for murder.
“My dad tells me the story about what it was like when I won my first world title where he was in a cell on his own," he said .
"And the story was just so different to this one. For him to be here, for him to see it, for my kids to be here. My dad’s had a great time here. The kids have had a lovely time. I didn’t think I’d make another world final so I said you may as well come down and try and experience it."
Ronnie Jnr, from Chigwell in Essex, was just 16 when in 1992 his dad, then 37, was caged for the murder of dad-of-two Bruce Ryan.
Ronnie Snr made millions running a string of sex shops in Soho and was said to be well known in the London underworld.
“It was a very murky world, not one I entered out of choice,” Ronnie Jnr said. ”But that’s what happens when your dad is involved in an adult bookshop up the West End.”
His dad had been on a night out when he fatally stabbed Mr Ryan, the driver for Charlie Kray the elder of the infamous Kray twins – inside a nightclub on Chelsea’s trendy Kings Road.
He had been on a drinking binge with a friend when he went "looking for trouble" at the club, prosecutors said, before he set upon Mr Bryan and his brother Kelvin, allegedly hurling racist abuse at the pair, who were black.
Witnesses said he then pulled out a six-inch hunting knife and stabbed his victim to death.
Kelvin later said: "It was like a horror movie. He turned on Bruce and began stabbing and slashing at him with a huge knife. My brother had his arms up as protection but O'Sullivan was in a frenzy."
Ronnie Snr has always argued the unprovoked attack was not racially motivated. Ronnie Jnr has stood by his dad, insisting he'd "never been a troublemaker” and had fallen with the wrong crowd.
"He was in the wrong place at the wrong time and it certainly wasn't a murder” he said. “It certainly wasn't premeditated murder."
Ronnie Jnr has previously spoken of how he was left with the task of trying to track down a witness to his dad’s crime.
“The loyalty I felt towards my dad . . . I’d do anything he asked,” he told The Sun in 2016. I had to meet certain characters I would never normally have met. For quite a while they were in my life — not that I wanted it, but I had to do it for my dad. Before I knew it I’d got psychopaths as friends. I really tried to find that witness but I failed. At the end of the day I’m a snooker player, not Columbo.”
Ronnie Snr was given a life sentence with a minimum term of 18 years.
Snooker prodigy Ronnie Jnr, who began playing in a snooker room built by his dad at the bottom of the garden at the family home, was dealt another cruel blow when aged 19 his mum was jailed for a year for tax evasion leaving him to look after his then eight-year-old sister Danielle and the family business.
Ronnie Jr became world king for the first time after beating John Higgins in the 2001 final. He said early in his career that knowing his dad would be watching him play from prison was one of his primary motivations.
“My dad used to say it was like a visit to him when he saw me on the TV” he said.
"I thought, ‘Bloody hell, that’s got to be the most important thing, it’s keeping him going’” So I knew I couldn’t give up, even though I was hating it. I couldn’t deprive my dad of that.
He has previously claimed he thinks his dad’s sentence had a profound effect on his career and how it developed.
He believes he would have become a world champion sooner, and won ever more tournaments, had his dad been there to guide him.
"To not have him there was tough, it was teamwork,” he told the Daily Star in an exclusive interview in 2020.
“From 1995-to 2000, I won a few tournaments but I was never really consistent as much as I should have been.
"I wasted probably five years of my career, messing about really. Once I’d won the UK Championship (his first ranking title) there was a monkey off my back. But dad was away and when he went away it took me a year for me to get my head around accepting that he wasn’t going to be around.
“But in a way my intensity level dropped a little bit, I started enjoying myself a bit too much thinking that I’d made it, when really I hadn’t, it was just one tournament.
"I think it would have been a lot different. I think I’d have won the World Championships a lot earlier and won plenty more tournaments." "Absolutely, 100% it would have been different" he added.
"But it was what it was, it was unfortunate for me and him. Things could have been so much better. I certainly would have enjoyed my career a lot more having him around than not having him around."
Ronnie Snr was released from prison, after 18 years inside, in 2010, after previously being allowed out on day release as part of a rehab scheme a year earlier.
He is now reportedly living in a campervan with a woman half his age.
He is reportedly 'embracing full time van life' with health drink entrepreneur Tiffany Kushner, 34, after they became 'bored with comfortable living' and splashed out £94,000 on a luxury Mercedes motorhome the Daily Mail reported in February.
It's not clear when they met but there are pictures of them together as far back as 2020. In a video posted on social media, Tiffany said their ambition was ultimately to 'get our own plot of land to live sustainably and grow our own food.'
On Monday, Ronnie Jnr became the game's oldest ever world champion, equalling equals the seven world titles won by Scot Stephen Hendry.
And afterwards, he said it was made all the more special by the fact his dad was there to see it.