Both teams had to contend with awful conditions, with driving rain and swirling wind preventing either side from playing much rugby.
Ballymena started on the front foot, and Campbell spent most of the opening 20 minutes defending inside their own half.
However, their first real break into the Ballymena half proved decisive. Out-half Peter Dorrian combined well with his centres, Ollie Park and Henry Ralston, as Campbell worked their way into the 22 with a flowing move.
They were stopped short, but the ball found its way to number 8 Callum McKinney who crashed over from close range for the first try of the game with 22 minutes on the clock. Outside centre Ralston added the extras to send them into a 7-0 lead.
It sparked an immediate response from Ballymena, who touched down in reply just 3 minutes later. A few well-worked phases saw the ball end up in the hands of number 8 Charlie Hargy, and he showed great strength to power through the defence and score in the corner.
Campbell soon extended their lead with a stunning solo try from Ralston.
As the Campbell backline tried to return a kick, they appeared to have lost control of the ball through the hands - only for Ralston to scoop it up from the deck near the half-way line and weave through defenders as he seared through to score the decisive try.
It came in the 29th minute and put his side 12-5 ahead at half-time.
As the second half got underway, the influential Ralston slotted a penalty from just outside the 22 as Campbell began to control the game.
With 41 minutes played, Campbell grabbed another try to further extend their lead.
More good work from Ralston saw the ball moved wide and into the hands of Ed Thomas, with the winger showing impressive speed and power to break two tackles and then stretch for the line to score in the corner to make it 20-5.
As the clock ticked down, Player of the Match Ralston again stepped up to slot a penalty to give the game a final score of Campbell College 23, Ballymena Academy 5.