In 2009, Johnson returned to the United Kingdom but despite his children being born in Scotland, he said his family saw themselves as Kiwis and Rotorua as a great place to live.
"Rotorua has the potential and the people I'm working with are just top class, in terms of the board, they are good and the coaching team is really, really strong. I see the potential here for Rotorua to have plenty of success."
But first, there is plenty of work out of the pool.
"What I'm doing at the moment is I'm auditing, what goes on, what the structures are, what the pathway is and building relationships to the people here who are very good and getting to know the athletes. "It is all looking very positive and I can see we are going to grow enormously.
"So my basic goal is to grow the club membership and have a much bigger number of athletes training and competing. That's going to be my main focus."
Johnson said he wanted to see more athletes from the club competing on the national stage and possibly the international stage as well.
"It's hard to say at the moment, how far we can go, because it's just too early.
"But my job is to maximise the potential we have and to produce really good [swimmers] always."
The father-of-two said former club members, national open water champion Kane Radford and Olympian Carl O'Donnell had set standards that children at his club would aim for.
"We've already had two people who have padded the way and people know of them as local lads who've done well.
"So, obviously, if its been done before our job is to replicate that."
Johnson said the current young swimmers in the club had impressed him.
"There are always good kids where ever you go. The really important thing is to nurture them properly, so they get all the right ingredients to see swimming as their sport, to be committed to it, to get into good habits and so on," he said. "So there are some really good kids [here] but they are not on anyone's radar as yet.
"But what we need to do with them is give them the ingredients for success. Because success takes a really long time."
Although there is the potential to get the club gaining national honours straight away.
Johnson said it was better to build slowly rather than getting instant results.
Swim Rotorua are always looking for new members interested in joining the club.
This can be done by email: swimrotoruraadmin@gmail.com or phone (07) 333 2642.