After the game both managers agreed that the windy conditions had played a vital part in the outcome as the Cobblers hit back to win a fluctuating encounter.
Even though Calderwood was sent to the stands late on for abusing the fourth official, the damage had been done.
Calderwood brought on substitutes Charlie Hearn and Pedj Bojic and within ten minutes of the second half starting Northampton had turned a 1-0 deficit into a 2-1 lead.
After striking twice and with the wind at their backs Northampton looked a class above Grimsby with their strong and fast running from midfield.
It had been a different story in the first half though when, with the wind at their backs, Grimsby deservedly took a 20th minute lead.
The Mariners' goal came when Thomas Pinault's corner was headed goalwards by Martin Gritton and Michael Reddy applied the finishing touch from close range.
Northampton drew level in the 48th minute when Grimsby keeper Anthony Williams failed to hold on to Trevor Benjamin's shot and Scott McGleish pounced to sweep home the loose ball.
Six minutes later Benjamin had a free header as he steered home Northampton's second.
There was no way back for the Mariners who had the stuffing knocked out of them by the double strike and substitute Ashley Sestanovich did not help his team-mates by getting sent off within four minutes of coming on for swearing at the referee.
Northampton's win puts the pressure on the top three in League Two and on the second-half form they look a good bet for automatic promotion.