However, St Kents, with a strong wind at their backs, led only 10-3 at the break. Both sides started at a furious pace and some of the defence was brutal, exemplified by St Kents tighthead prop Jethro Felemi's hit on his opposing lock Sam Chongkit.
Second-five TJ Faiane danced his way over for the game's sole try near the end of the first stanza, while No10 William Raea added the extras.
Heavy rain arrived not long before halftime, making the ball like soap. The home side dealt better with the adverse conditions, pressuring St Kents with some committed defence and weight of possession.
Perhaps the key moment of the clash was Hamilton BHS second-five Mikaere Beattie's try-saving tackle on St Kents wing Harry Marks.
From then on, the hosts were able to control field position, and keep the ball away from dangerman Suliasi Vunivalu, despite captain Harrison Levien having a difficult day at the scrumbase with his clearances. St Kents captain Blake Gibson tried valiantly to rally his troops, but to no avail.
Flanker Blake Bolli was twice close to scoring for the home team, and three minutes from time, first-five Bryn Gatland slotted a dropped goal, his first of the season. It wasn't the prettiest three points but it was gold to his side and supporters.
"This is a fantastic team of young men, with strong leaders and nice boys. Nice boys don't always win championships but these boys did," said co-coach Nigel Hotham, the 2012 New Zealand Schools coach. "One of the most emotional moments of my rugby life was to see what it meant to this school at that final whistle."
Hamilton BHS last won the title in 2009, defeating St Bede's of Christchurch in the final.
Hamilton Boys' High School (B. Gatland 3 pens, dropped goal) St Kentigern College (TJ Faiane try; W. Raea con, pen). Halftime: 10-3 St Kent's.
