The Northern Irishman beat off competition from nine other finalists in a head to head cook-off at The Restaurant Show at Olympia today (4 October).
Second place went to Adam Thomason, head chef at Deloitte, Restaurant Associates, while Charles Smith, head chef at Alyn Williams At The Westbury, took third.
Devine - who became a chef after abandoning plans to study law - said: "I never expected to win or even get this far. It's a real honor to be standing here. I can't wait to tell everybody back home - come on Northern Ireland!"
All 10 finalists were tasked with cooking a three-course meal in front of a Michelin-starred judging line-up including Clare Smyth, Philip Howard, Andrew Fairlie, Claude Bosi and Sat Bains.
Devine impressed judges with his starter of tortellini, roast chicken, butternut squash and sage veloute; a main course of tees valley rib of beef, braised puy lentils and watercress; and a dessert of soft centered chocolate and coffee tart with passion fruit curd.
As part of his prize he will make a guest chef appearance at Le Cordon Bleu in London and take part in a study trip to Switzerland with Nespresso.
Chairman of judges Clare Smyth was full of praise for all the competitors.
"Year on year we keep getting surprised by people," she said. "It's a really brave thing to do to come out of the bubble of your own kitchen and be judged publicly."
Run by the Craft Guild of Chefs, the National Chef of the Year is regarded as one of the UK's toughest cooking competitions.
Previous winners have included Gordon Ramsay, Alyn Williams and Mark Sargeant.