"I didn't grow up with horses as such and only did a bit of hunting with the Clare hunt as a teenager.
"My wife Ann though comes from a horse background and our daughter Rachel absolutely loves them.
"We only have two acres here at home in Kildysart, so I only ever have room for one horse.
"A friend of mine, Michael Purcell, told me about a mare that Marion Hughes had, so we made an offer to buy her in February of last year."
By Billy Twomey's former mount Je T'aime Flamenco, the mare Aidensfield Flamenco boasts an impressive jumping pedigree.
It is something that O'Sullivan believes firmly stood to her during the RDS qualifiers, and ultimately the final.
"I was specifically looking for something that would breed for performance," he said.
Purchased as a four-year-old, she had been surplus to Marion Hughes' requirements, but her bloodlines on paper would make her a top-class broodmare.
Je T'aime Flamenco needs no introduction as a winner of a host of international competitions, including the four-star Grand Prix in Amsterdam on three occasions.
The dam HHS Charmed is a half-sister to HHS Charmer, Prince Cavalier, Cavalier Charisma, and HHS Royal Card.
All are out of the Diamonds Are Trumps mare, Noble Trump.
"With that pedigree I decided to send the mare to the Oldenburg stallion OBOS Quality 004 and she produced a smashing colt foal."
Initially O'Sullivan did not think the combination would be ready in time for the qualifiers, but thanks to his brother Brendan, they headed to Athlone in a bid to secure a place in the Breeders' Final.
"I had already seen the results of the qualifier in Galway and that foal was by OBOS Quality 004 as well, so I was somewhat optimistic."
On the day of the qualifier judges Maurice Coleman and Susan Storey were immediately drawn to the mare and foal and they passed through with flying colours.
"I was delighted as Susan believed they would also do well in Dublin, and that gave me the confidence to ensure they were in peak condition."
A plumber by trade, O'Sullivan works by day, and so a lot of the preparation was done in the evenings. "My brother Brendan was fantastic and put in long hours as well so it was only right that he would lead up the mare on the day."
It was a day they would never forget as they were called to the top of the line-up by judges Fred van Straaten and Egbert Schep.
"I always maintained our foal was the type they would look for, as he is so athletic, so it was fantastic to see all our hard work paying off."
O'Sullivan had no sooner left Ring 1 when the foal was snapped up by the sire's owners, Bill and Kieran Kennedy.
O'Sullivan said he has also received offers for the mare, but as yet he is in no rush to sell.
"She is a mare of a lifetime and she's still only five, so it would need to be a serious offer."
This year she was covered by Zapatero, who won the KWPN Grand Prix for Jessica Kurten in February. It was to be the Irish rider's final appearance in an international arena.
By Chin Chin and available to breeders in Ireland through Kylemore Stud, Zapatero's jumping pedigree also caught the eye of O'Sullivan when looking for a suitable sire for his 2016 showing campaign.
"For me now it's all about performance and I hope that one day my mare's progeny will go on to prove that," he concluded.