As a result, he said one of his strengths was his ability to motivate teams he coached and to build a culture where players want to overachieve.
"I like to think that I have the ability to motivate and draw the best out of players," he said.
"I think that has largely come out of the fact I have always been involved with teams that, I wouldn't say were underachievers, but battlers.
"I have always been a battler.
"When I was at Whaka we had a couple of good years but generally we always battled.
"Largely through my time with Bay of Plenty we were in the second division. We were up the top there, but there were still battles. Then we got up to the first division and for the first two years we were there we played promotion/relegation matches and it was a battle.
"I went over to Japan and I played for, initially, a second-division team that had great aspirations of being promoted to the top league, and within a year we got promoted.
"So I have been in teams that have always been the underdog, I guess, and when you are in a team like that and perhaps don't have as much talent as the other teams have, you have to be able to find that extra 5 per cent from somewhere. And a lot of that is around motivation and building a culture where people want to want to overachieve."
He said he was looking forward to the challenges ahead with the Steamers.
"In a lot of ways, coming back to the Bay, there is no bigger challenge, but that is something that I am keen to embrace."
Since taking up the top job at Bay of Plenty Rugby in November, McMillan has put a big focus on building bridges across the province.
He said, first and foremost, there was a great need to have a unified Bay of Plenty. "I would argue that it is probably more important than getting some good results out of the Steamers."
He has been travelling to all corners of the province with his high-performance players, rather than just staying put in the Western Bay, to be visible across the region and help grassroots coaches. He said he was 100 per cent behind a unified Baywide club competition as well, and was glad the subunions did not break away and start their own competitions at the end of last year.
McMillan said he was not content to label this year's ITM Cup campaign a development year for the Steamers.
"Coming in off the back of a couple of fairly disappointing seasons it would be easy to come in and say this year is about development, but I don't necessarily see it that way.
"I think if we get our prep right and select the right players then we are in it to do well.
"So I don't really subscribe to that whole 'this is a development year'. We just need to be better."
Since retiring from his playing career, McMillan has built a good CV coaching premier club sides in the Bay of Plenty and Wellington.
His most recent coaching achievement was taking the Wellington under-19 team to the national under-19 title in Taupo last year.
He has not coached at ITM Cup level before.
The Steamers have won only three games in the past two seasons.