Brown's Northland teammate Kadin Neho (Whangarei) was leading heading into the final round and playing in the last group as his main challenger.
Despite this, some uncharacteristic mistakes by Neho on the closing stretch saw Brown's lead hold up by the narrowest of margins.
Looking ahead to this weekend, the Northland team will take on North Harbour for the annual Great Northern Battle at Mangawhai on Sunday.
With Brown earning a well-deserved spot in the Open Men's squad, he said his confidence had grown as a result of the long-awaited Bream Bay Classic win.
"I'm really stoked, I've been working at it for a while. I'm going to be working hard the next couple of days mainly [on my] wedge shots and my short game, putting and what not."
In the women's competition, it was an emphatic win for Waipu local Kylie Jacoby.
A regular contender at the event, Jacoby led from start to finish with rounds of 75, 74 and 76 to finish at six over par.
Krystal Hu (Gulf Harbour) finished runner-up, some 15 shots back with Alyana Cox (Wellsford) in third.
Rain on the first day led to some of the second rounds finishing the following morning.
The winner of the Masters division was Michael Barltrop of Royal Auckland and the runner-up was Rob Simmonds of Muriwai.