He won several national-level medals and his breakthrough win of a New Zealand title in the 400m medley in 1993 was a crowning moment.
Then he turned to forge a successful career in triathlons, becoming one of the best swimmers in the international competition.
But those days are long gone and now his attention is on future athletes through his own event.
The Summer Swim Series is in its second year and attracts an average of about 250 athletes who compete over a range of distances.
"We pride ourselves on running a professional event without being obnoxious," said Woolley.
"It is a really popular event because of the relaxed feel - there is no stress. Anyone is welcome and everyone who races is approachable.
"The best guys are always around afterwards and willing to give tips to the guys looking improve."
The series consists of 16 weeks of competing, and attracts athletes of a wide range of abilities and ages.
Swimmers include teenagers and 60-somethings, but the average age is about 40.
For the elites, the Summer Swim Series offers perfect training conditions because no other events offer a regular 2km swim.
This makes the longest race option swim the most popular, attracting about half the field every week.
Elite swimmers Kane Radford and Brent Foster have swum in the series, and Molly Swanson is dominating the women's division.
"The elites love it because it is perfect training for bigger races like the swim in the half ironman or the other long open-water events," said Woolley.
"There is always good competition at the top of the field and that helps the best get better."
Another factor that all serious swimmers appreciate is the accuracy of the course.
Woolley said the organisers took pride in making sure the distances were always within 5m of the specified distance to ensure the times were a good reflection of where athletes were with their training.
"It means you don't have anyone to blame but yourself or your training if you don't record a good time."
Woolley said competition to win the titles in the Summer Swim Series was intense, but only to a point, with swimmers keeping an eye on the bigger picture.
"There is a trophy on the line and bragging rights that go with that, but most of the guys just want a good regular hit out."
Woolley offered some simple advice for newcomers who think they can just turn up and complete the 2km swim.
"I would recommend that you don't do it unless you have proved to yourself that you can swim that distance in training.
"Also, there is a big difference between swimming 2km in the pool compared to ocean swimming.
"The waves and the need to navigate yourself over that distance really take it out of you, so you need to be ready for that.
"It is all about being confident in that distance and also comfortable in that environment."
High-achiever
Haydn Woolley won several national-level medals in the early 90s. His New Zealand title in the 400m medley in 1993 was a breakthrough win.
In the same year, he set a New Zealand open record in the 3000m freestyle event.
When he turned his hand to triathlon, he quickly emerged as one of the top two swimmers worldwide in the sport.
This was shown by his lead from the swim leg in the 1995 world championships in Cancun, Mexico.
He went on to record a world record time in the 1997 Auckland Ironman - 43.30min over 3.8km.
However, this was not an official record because Woolley didn't finish the run as a result of stress fractures. No triathlete went faster until 2004.
Series CV
The Summer Swim Series
Weekly ocean swimming event that allows competitors to choose from four race distances.
Distances: 500m, 1000m, 1500m, 2000m - accurately surveyed courses.
When: Starts 6.15pm every Thursday. Registration 5pm to 6pm.
Where: Kohimarama Beach, close to the Kohimarama Yacht Club.
Last swim in 2011: December 22.
First swim in 2012: January 19.
Multi-talented Swanson chasing outright win
Molly Swanson is not the type of woman who looks back at her rivals in her wake.
She is more focused on what is ahead of her in the Summer Swim Series and claiming one of the 2km race wins from the leading men.
The 18-year-old from Mt Albert Grammar School, who is also talented in a number of other sports including athletics, cross-country running and orienteering, has dominated the female division of the 2km event on Kohimarama Beach this year, winning four out of the five events by huge margins. It would mean the world to her to have the bragging rights over the men with an outright win.
"That would be pretty cool, actually," said the bubbly prefect from MAGS, who had just returned from two-and-a-half hours of training, completing eight reps of 1km.
"I have been close a few times when the course has looped around and I could see the men's leader. I would love to beat the guys and I am going to keep pushing hard to stay in touch. If I won, I'd be pretty chuffed."
Swanson said competing with the depth of quality men in the ocean swimming events has taken her to a whole new level.
"There are about four to six guys who set a really good pace and I try to stay on their slipstream ... having them there has helped me improve out of sight."
She is using the series to prepare for the 10km race in the Epic Swim at Lake Taupo on January 14. But it would still be a significant achievement to finish on top of the women's division, as she hasn't enjoyed too many accolades in swimming.
"That would be pretty special," she said. "I didn't win a lot as a pool swimmer and I feel like I hadn't really blossomed until recently, really.
"To win a series like this one would be something I would be really proud of."
With a host of sporting pursuits and the desire to study medicine at the University of Auckland next year, life is busy for the prodigious talent.
Swanson, who now swims at the Laser Mt Eden Swimming Club, said the Summer Swim Series has been great for developing her confidence as she considers taking an elite swimming career more seriously. "I have real belief in my potential now. A while back, I wasn't getting any results and I was down on myself and just not enjoying it. But with every swim, that has got better, and the improvements I have made with my coach [Glen Hamblyn] have been great.
"I am faster and can go for longer and swimming is really fun again."
Series organiser Haydn Woolley has been very impressed by Swanson's ability. "Molly is absolutely killing it at the moment and she is in her own race every time she swims."
"I am not too close to the [Swimming NZ] high performance at the moment, so I don't know where she ranks, but she can't be too far off because she is an exceptional swimmer."
Swanson is aiming to complete the Taupo marathon swim in 2 hours 20 minutes.
"It's my first swim of that distance, so it's hard to say how I will go, but I feel like I am well-prepared. It is going to be a good challenge and if I do well I could look at taking swimming more seriously or maybe try some triathlon events."
Molly's advice
"Don't give up. There are going to be times out there in the water when it is really hard, your legs and arms are aching and all you want to do is stop, but you have to keep pushing through. It is so much harder when you stop. It is an amazing feeling when you reach the shore and you have finished a big swim. It is an achievement to be proud of. "
