"Last year I finished in 11hrs31m. This year I wanted to go under 11hrs and thanks to ideal conditions and getting the nutrition right I managed to do it," he recalled.
"I finished the swim a minute faster than last year. I completed the cycle in 5hrs33m but there were still people flying past me on flash bikes. I knew if I did the marathon under four hours I would get there ... I did it in four hours and 43s, a dream run."
A father of two daughters aged 5 and 3, Johnson was full of praise for the work physio Justin Mills did on his body.
"Last year I had neck, back and knee issues. I trained for the December Half Ironman in Taupo and when I finished that I only gave myself a 20 per cent chance of competing at the weekend because my back was so sore.
"It was January 4 when I decided I would do the full Ironman. I trained in the hot conditions of January and February in case it would be hot at the weekend and we got those conditions," Johnson explained.
Last year he dropped his bike during transition and lost four gears. There were no such problems at the weekend. "I enjoyed it as much as I could when you are doing something like this for nearly 11 hours."
Like his former Magpies teammate Jason Bird who stopped the clock at 12:45:01s, Johnson said the time required for ironman training is the biggest difference from his professional rugby days.
"Obviously the physicality isn't the same. It wasn't uncommon to do 15-20 training a week including a six-hour cycle at the weekend. My wife Caroline has been extremely supportive," Johnson said.
Although he has dropped 8kg from his rugby playing days, Johnson said there are still plenty of triathletes who tell him he looks more like a rugby player than a triathlete.
"I tell them I played a bit of rugby in my younger days," Johnson said with a laugh.
The self employed builder said it's still too early to decide whether he will tackle a third consecutive Ironman next year.
"Last year I said never again. I've got a couple of mates who watched me at the weekend who are keen to do it with me next year but we'll wait and see."
His immediate priority is Sunday's Tremains Triathlon in Napier. He has done it for the past five years and does the run leg for a team which also includes cyclist Tama McGrath and kayaker Glenn Thompson. They have won their team division for the past three years. Johnson will again hope to go under 20 minutes for his 5km run. It's obvious he is addicted to the triathlon scene.
"Triathlon Hawke's Bay boasts an awesome club environment. A lot of the IronMaori competitors are involved and when we watched the final two hours and saw people we knew coming in and their emotions and people crying it's easy to see why we get addicted.
"In rugby you have Richie McCaw. In cricket you have Brendon McCullum and in Ironman you have Cameron Brown. Well I got to have breakfast at the same place as Cameron the following day and I shook his hand," Johnson added, referring to the 12-time winner of the men's elite title.
