The 36-year-old Hill City-University runner first fell in love with athletics as an 8-year-old, when he competed in his first harrier event, the Winding Vine Relay.
His family followed him closely in the car around the twists and turns of the Otago Peninsula, with the rain pelting down around him.
"Everyone was worried that I’d gone out too quickly and was gonna not make it to the finish," O’Sullivan said.
"After the race, Mum picked me up and had to carry me back to the car.
"It was the race that opened the door for my life-long passion for running and now coaching."
O’Sullivan is lining up for it again tomorrow, with the event - an evolution of the former Peninsula Relay and renamed to follow the trail’s official name, Te Aka Otakou - back on the calendar for the first time since 2020.
The handicap race is split into five legs, starting in Portobello and finishing in St Leonards, and has attracted strong entries.
It was suitable for all ages and was a good event to get people into the sport - with the handicap element adding something unique as "you never know who is going to win", he said.
"I think it’s just the real camaraderie that’s built during these team relays.
"Just with it being such an individual sport, it’s just really nice. You’re always competing against everybody, including people in your own club, so these events are just a real nice way to bring people together to have that common goal.
"You are never too old or young to become involved, and I would love to see more people enter the sport. We have a supportive and friendly community and we encourage people to reach out."
O’Sullivan has had a standout season so far too, winning the men’s 35-39 years grade world cross-country title in Bathurst in February and adding a national and Otago cross-country title to his resume.
"Running is a sport for all abilities and stages of life.
"I still compete just as competitively as I did as a child and some of my greatest achievements have come in recent years."
