Mr McKenna's postings have included heading several prestigious hotel and restaurant kitchens, including Dublin's National Yacht Club, Planet Hollywood and Morton's - the high-end Dublin equivalent of London's Harrods Food Halls.
In recent years Mr McKenna forged a niche for himself as a specialist food consultant, rescuing and reinventing high-quality establishments in Ireland. He has also run his own fine-dining restaurant and tutored at Dublin's Cooks Academy.
Mr McKenna said he was "really passionate about food" and described Wairarapa as "a real breadbasket of produce".
Mr McKenna cites local farmhouse cheeses and lamb as examples and notes that with nearby vineyards, "you don't have to go very far to match wines".
While The Grill will have a new summer menu early next year, the new head said he first wants to get a feel for what his customers want and like. "It's not about me showing off; it's about creating a dining experience that our customers are comfortable in, that they enjoy, will return to and will tell their friends about."