Felipe Nasr, Nick Tandy, and Laurens Vanthoor took victory at Sebring International Raceway in the #7 Porsche 963, leading home the sister #6 entry by 2.2 seconds. Campbell was second alongside Mathieu Jaminet and Kevin Estre.
Porsche almost locked out the podium until the #5 Proton Competition car of Neel Jani, Nico Pino, Tristan Vautier was forced to pit late for fuel.
Alex Palou, Nick Yelloly, and Renger van der Zande rounded out the podium for the factory Acura team Meyer Shank Racing in the front-running #93 ARX-06.
It’s the 19th win for Porsche at Sebring and the first win for them since 2008.
“The one-two finish is obviously a banner result for Porsche Penske Motorsport,” said Campbell.
“Congratulations to our victorious sister car. Today was incredibly long and tough for us; the race went back and forth.
“We experienced some difficulties in the intense heat of the early afternoon, but our Porsche was incredibly strong in the cooler evening.
“It’s terrific to score the maximum number of points together.”
New Zealand’s leading interest Earl Bamber finished fourth in the Whelen Cadillac V-Series.R alongside Jack Aitken and Frederik Vesti.
Scott Dixon was only 10th in the #60 Meyer Shank Racing Acura car with Tom Blomqvist and Cloin Braun. The Kiwi finished five laps down after contact in the pit lane between Blomqvist and the #24 BMW M Team RLL of Phillip Eng/Dries Vanthoor/Kevin Magnussen caused suspension damage to the #60 ARX-06.
“Definitely a trying day for sure,” said Dixon.
“We had a burst of speed here and there. I think we could have fought for the podium but ultimately we had the pit stop altercation with the BMW and that kind of took us out of it.
“But huge thanks to the crew for getting the car back together so that we could at least finish out the race.”
Brendon Hartley wound up 11th as a late call-up for Wayne Taylor Racing in the #40 Cadillac. He had his own issues, which took the car he shared with Jordan Taylor and Louis Deletraz largely out of contention.
“It was a bit of a rough day on both sides of the garage,” said Hartley.
“We were battling and everyone was doing their best. I had a little mistake, I had been struggling a little bit with brakes, locked up and went straight into Turn 17 which lost us a lap.
“And then we just couldn’t get it back. Not many yellows, which was a problem for both cars to get us back to the lead lap. I think we battled hard, but ultimately, we left here with no result.
“Disappointed and I feel bad for making an error but I enjoyed my weekend with Wayne Taylor Racing and hope to be back at some point.”
In LMP2, New Zealand’s Hunter McElrea claimed third for TDS Racing. Australia’s Josh Burdon was fourth with Riley.
Tom Sargeant finished fifth in GTD with Wright Motorsports while Lone Star Racing’s Scott Andrews had late issues that relegated them to ninth.
IMSA continues with a 100-minute race at the Grand Prix of Long Beach on April 13.