Saturday night ended a "real rollercoaster" of a journey, which began when he missed out on National Party selection in 2011, he said. He lost again before the by-election, before finally succeeding in November.
As an unknown against a "rock star" opponent, he had done the hard yards, knocking on doors over the last 10 months.
He paid tribute to the support he had received, especially from his wife Sarah, while his priorities would be building infrastructure, addressing social issues and seeing Ngapuhi settle its Treaty claim.
And National would never take Northland for granted again.
Meanwhile, Mr Peters said losing the electorate was "a terrible shame", but he had given it his best shot.
"I was very privileged for a brief time to be their MP, but now I've got more time to be an MP around the country," he said.
Hone Harawira, who failed in his bid to unseat Labour deputy leader Kelvin Davis in Te Tai Tokerau, said the fight for his people would go on whether he was in Parliament or not. He was saddened by the demise of the Maori Party, however.
"That's a huge loss," he said.
"Maori no longer have an independent voice in Parliament. It's just the two major parties, who will tell their Maori MPs to shut up, these are our priorities."