Bamber joined Jack Aitken and Frederik Vesti on the top step of the podium after winning the six-hour race in the #31 Action Express Racing Cadillac V-Series.R prototype.
Aitken took the chequered flag ahead of Ricky Taylor, who surged late to take second place in the #10 Wayne Taylor Racing Cadillac with Felipe Albuquerque.
Tom Blomqvist and Colin Braun were third for Meyer Shank Racing in their #60 Acura ARX-06, having briefly threatened the race-leader Cadillac in the closing half an hour.
A late full-course caution set up a two-lap dash to the chequered flag, but there were no major changes at the front of the GTP field.
Australia’s Matt Campbell was seventh in the best of the Porsche 963 entries with Porsche Penske Motorsport co-driver Mathieu Jaminet.
It marked the first win for the Whelen-backed Cadillac team this season.
“It’s an amazing result,” said Bamber.
“I think everyone at Cadillac has been really pushing the whole year, so to get that first win now (this season), our first podium for us in a long time.
“The guys at Whelen Cadillac have been amazing. They’re the best in pit lane. They’re the best up on the timing stand, so it’s a huge amount of work and effort.
“Hopefully this opens the floodgates to many more.”
LMP2 honours went to TDS Racing, led by New Zealand’s Hunter McElrea with Steven Thomas and Mikkel Jensen.
Australia’s only entry in LMP2, Josh Burdon, was third for Riley with Gar Robinson and Felipe Fraga.
It’s the second year straight that McElrea have won the Battle on the Bricks.
“Coming into the weekend, we knew we had the fastest car,” said McElrea.
“Finally, we just executed a clean race and the win was ours. Amazing job.
“Steven, he was incredible all weekend. Amazing stint from him. Obviously, Mikkel brought it home like always.
“So happy for the team, happy for myself, happy for Mikkel, happy for everyone because we all really needed a win. Coming back here, we seem to own this place.”
Supercars Sprint Cup winner Broc Feeney and expat Australian Kenny Habul failed to finish in GTD Pro. The #75 Mercedes-AMG for 75 Express that they shared with Mikael Grenier cried no more after 123 laps and was forced to retire.
GTD Pro honours went the way of Ford with Mike Rockenfeller and Sebastien Priaulx in their Mustang GT3 ahead of the DragonSpeed Ferrari 296 GT3 shared by Albert Costa and Davide Rigon.
In GTD, Thomas Sargent claimed second place with Wright Motorsports in their #120 Porsche 911 GT3 R alongside Adam Adelson and Elliot Skeer.
Scott Andrews was a non-finisher after the left rear wheel of the Lone Star Racing Mercedes-AMG GT3 parted company in the final hour.
The class win went to the Ferrari 296 of Inception Racing.
One race remains in the IMSA SportsCar Championship with Petit Le Mans at Road Atlanta on October 12 (AEDT).
CLICK HERE for IMSA Battle on the Bricks results
CLICK HERE for IMSA Battle on the Bricks results by class
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