Hoang beat six other finalists, four of whom won their place by competing in other events and competitions, to the title following the final at The Restaurant Show at Olympia on Monday.
Second place went to Danny Young of Northcote Manor while third place went to Ruth Hansom of The Ritz in London.
All seven finalists were tasked with cooking a three course meal using a list of ingredients issued last month.
Hoang's menu of Roast quail breast with hay-baked beetroot, watercress and parsley sauce, and pickled beetroot; Seared hake with baby leeks, mussels, celeriac and sea vegetable vinaigrette and Spiced bread and butter pudding with vanilla ice-cream and malt custard, pickled blackberries and Braeburn apples impressed judges who included
Hoang told BigHospitality he couldn't believe he'd won the competition.
"The first thing I thought after the competition finished was what I could have done better and the things I should have changed and I sort of doubted myself afterwards, so it's definitely a surprise that I won," he said. "But now that I look back at my dishes I can see everything clicked in to place."
Chair of judges for Young National Chef of the Year, Mark Sargeant praised the standard of all the finalists.
"These guys hold their own against those competing in the National Chef of the Year. They are fantastic and talented beyond belief," he said.
The Young National Chef of the Year competition is open to chefs aged between 18 and 23 and runs alongside the National Chef of the Year.
Typically four young chefs automatically win a seeded place at the final, made up of winners of young chef competitions from the British Culinary Federation, the Academy of Culinary Arts Awards of Excellence, the Craft Guild of Chefs' Graduate Awards highest achiever and WorldSkills.
The remaining four places are made up of the winners of two semi-finals to which up to 20 young chefs from industry wide competitions including The Craft Guild of Chefs Graduate Awards, Young Welsh Chef of the Year, Young Scottish Chef of the year, Chaine des Rotisseurs Young Chef, Young Game Chef of the Year, Young Grampian Chef of the Year, Young North East Chef of the Year, North West Young Chef of the Year, South West Young Chef of the Year, will be invited to compete.