Lee and Troy Rohipa finished eight shots behind tied for second, with David Klein and Josh Carmichael four shots further back.
Geary says his start yesterday was definitely the winning of the Charles Tour tournament.
"It was a great start with those five birdies that opened up the lead," Geary said.
"I made some good putts and I drove it pretty straight. In those first few holes if you drive it straight and get up and down you are away laughing.
"My game was in good shape but mid back nine I had a couple of bad swings but that happens sometimes."
Winning in his home city means a lot to Geary who leaves today for two months of tournament golf in Australia.
"It is great to win here and have family support and friends out watching. It is cool to have that three from three record here and it is a course I like.
"There was a bit of pressure on me this week and I was three shots behind going into the weekend but I just stuck to my processes and it all came good in the end.
"Winning is always fun no matter what level you are at and it is a springboard for this summer.
"This win is great timing as the last few months have been pretty quiet for me so this is a great confidence booster."
Geary has been based in the US for the last four years and hopes to get back there someday as he says the courses suit his game.
But first he wants to get established on the One Asia Tour, where he has some opportunities to play.
Titirangi amateur Mun Chi Keh took out the women's tournament finishing eight-over.