The Pacific islanders, inspired by Mikaele Pesamino, stormed to a 17-14 win over Fiji in the final of the New Zealand leg of the tournament, having despatched South Africa in the semi-finals.
Victory represented a seminal moment for the traditional rugby minnows and left coach Dicky Tafua delighted.
"It's very important for Samoan rugby and I'm very proud," he said. "It's important that we've done it for the first time and with our home-based players."
England were relegated to the plate competition after a 14-7 loss to the hosts in the quarter-finals, and after beating Canada they were too strong for France in the final, claiming a comfortable 21-12 win.
Simon Amor, Rob Thirlby and Daniel Gray scored England's tries after they had fallen behind initially, and captain Amor was happy that playing in front of a large crowd at the Westpac Stadium had prepared his side for the challenges ahead.
He said: "I think we learned a huge amount across all the games here.
"We obviously look to be winning the cup competition, not the plate, but this tournament is magnificent and certainly for our young players here there's no better way to learn than to play in front of 35,000 Kiwis."
Argentina took the honours in the bowl competition, while Scotland were edged 26-24 by Portugal in the shield.
The result means there is all to play for ahead of next week's tournament in San Diego - the fourth of eight legs in the overall competition.
New Zealand and South Africa share the leadership on 48 points, with Fiji eight behind, while England and Samoa are well ahead of the rest of the competition with 32 points.