Mr Key said there was huge international demand for staging the tattoo so to have it in Wellington was a real coup.
He said he was focused on next year's event and it was too soon to say if the Tattoo would become a regular happening in Wellington.
The Prime Minister said he planned to be in the stadium next February.
"It'll be fantastic to see the stadium full. It will be a great spectacle of sight and sound."
Mr Key said it cost about $6m to bring the event to New Zealand but he expected ticket sales to exceed that.
The Tattoo last came to New Zealand in 2000.
"We know it will be a huge success. Essentially, last time it sold out [very] quickly. Our expectations are it will do the same."
He said he wasn't so sure if he'd wear a kilt to the event.
"I don't own one, but if someone lends me one I might."
Warriors performed a karanga and two dozen children dressed as Highland dancers greeted dignitaries at the stadium this afternoon.
Chief of Defence Force Lt-Gen Tim Keating and Te Papa chief executive Rick Ellis were among those joining John Key, who was promoting the event in his capacity as Tourism Minister.
Wellington mayor Celia Wade-Brown said the event, from February 18 to 21, would contribute about $14m to the local economy.
Tattoo chief executive and producer Brigadier David Allfrey said the stadium was "an amazing venue" and the last Tattoo was a big success.
"All the ingredients are here in New Zealand, and it's also of course got a tremendous Scottish heritage."
Mr Allfrey said bring the Tattoo to Wellington took four years of planning, involving negotiations with governments, armed forces, and civic leaders.
He said Scots were "delighted" their Tattoo was coming to New Zealand.
The event attracted about 220,000 people in Edinburgh but around 100 million people watched the Tattoo each year on international television.
Organisers in Scotland said 2014 was the Tattoo's sixteenth successive sell-out season, with about $21m in box office receipts.
