Jayasekara, who works at Petrus, wowed judges with his three course menu of Native lobster with red pepper, cardamom, leek and yoghurt; Roast loin of venison, celeriac and blackcurrant and Chocolate cremate with roasted pear and coffee.
The chef, who has made the competition's final three times now, said this year he had really 'pushed the boundaries' to create three 'consistent' dishes and ensure success.
"I never thought I was good enough," he said. "The standard (of the competition) is so high. The first year I reached the final, I thought, ok, the second year, I thought, ok, but the third year I really had to push the boundaries."
"It's not just about winning, it's about your career and what the title can do for it."
Jayasekara was one of eight finalists competing for the prestigious title and a number of prizes including a study tour of the world's best restaurants at the final at The Restaurant Show at Kensington Olympia today.
Second place went to Paul Foster of Mallory Court while third place went to Martin Carabott of the Royal Automobile Club.
Restaurant Gordon Ramsay chef-patron and chair of judges Clare Smyth, said the competition had been close and she and her fellow judges, who included Philip Howard, Daniel Clifford, Claude Bosi and James 'Jocky' Petrie had a 'tough battle' on their hands choosing one winner.
She said: "We weren't just looking for a great chef, but also an ambassador for our industry. Winning the National Chef of the Year is a real opportunity for chefs to raise their profile and get noticed in a tough industry. It brings everyone together and is helping to raise the level of gastronomy in the UK."
This year the title of the competition moved forward one year - to 2016 - to give the winner the chance to take the title into the next calendar year.
Entrants had to submit a paper entry before competing in semi-finals and taking part in mentor days and an interview process.