Crossing the finishing line in Auckland's Waitemata Harbour at 12:46pm local time (23:46 GMT), Dalton and his crew had fought off endless challenges over the previous 24 hours from the American Dennis Conner, skippering Toshiba.
The 1,270-mile leg from Sydney had taken four days, 23 hours, 16 minutes and eight seconds.
Despite winds of 30-45 knots and rough seas, Aucklanders turned out in their thousands to greet the crew of Merit Cup, which includes nine other Kiwis as well as the skipper.
Dalton paid tribute to two other boats after his victory.
"Fantastic duel with Toshiba this morning," he said, "and all last night, and I feel for Swedish Match, who were sailing a great race until they found a windless patch yesterday."
Toshiba finished three minutes 36 seconds behind Merit Cup, after the two boats traded tacks all the way across the Hauraki Gulf.
In third place was the American boat Chessie Racing, skippered by George Collins, 12.5 minutes behind Merit Cup. The current overall race leader, EL Language, was fourth but retained her overall lead.
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