The U.S. qualified directly for the Games by defeating the reigning Olympic champion Canada 1-0 in the CONCACAF W Championship final in 2022.
Jamaica, which lost 3-0 to Canada in the semifinal, defeated Costa Rica 1-0 after extra time in the third-place playoff to set up the playoff with Canada.
The Canadian women have taken part in the last four Olympics, winning gold, bronze and bronze after finishing eighth at the 2008 Games in Beijing.
Canada has won all 10 of its previous meetings with Jamaica, outscoring the Reggae Girlz 62-2.
Lacasse had the first scoring chance for Canada, taking a pass from Sydney Collins, going across to the centre of the field right in front of the box and sending in a shot that was stopped two minutes in.
Canada continued pressing with opportunities, but it was Jamaica that opened the scoring to the delight of its supporters.
Spence fired a free kick over Canada’s wall in the 33rd minute to capitalize on a Julia Grosso foul.
However, Lacasse made up for her missed shot in the 39th minute. After Ashley Lawrence hit the crossbar on a tipped shot of hers, Jamaica’s defence cleared it out of bounds following another Canadian chance in close.
On the ensuing play, Adriana Leon sent in a corner kick that met Lacasse’s head in stride to tie the game as the home crowd erupted with joy.
Huitema gave Canada a 2-1 lead in the 50th minute. Lawrence managed to outmuscle a defender to stay on the ball down the right side of the box and sent a cross in that was headed in by Huitema, who entered the game at the start of the half in place of forward Nichelle Prince.
Christine Sinclair, 40, started on the bench but entered the game for Leon in the 59th minute, receiving a standing ovation from the crowd. Two minutes later, Sinclair had fans on the edges of their seats as she almost scored but was stopped in close.
Jamaica, though, made a push with its own scoring opportunities. But with every missed chance — including a cross from Deneisha Blackwood to Cheyna Matthews that was defended well in the 73rd minute — the cheers only got louder from the Canadian faithful.
Although the Jamaican squad got more physical in the dying minutes of the game — both Blackwood and Spence were issued yellow cards in the 85th and 89th minutes — Canada kept its composure and held on to secure the win.