The rower from Coleraine took third place with a time of 7mins 3.28secs in the final of the men's single sculls at Eton Dorney on Friday morning.
It came just a day after he watched his Bann Rowing Club team-mates Peter and Richard Chambers win silver in the lightweight fours.
An exhausted Campbell was spurred on across the line by a "wall of noise" from Team GB supporters as he edged out Sweden's Lassi Karonen.
New Zealand's Mahe Drysdale took the gold with a time of 6mins 57.82secs and Czech Republic's Ondrej Synek took second with a time of 6mins 59.37secs.
"It was a very tough event," said the Team GB oarsman.
"They are the two best rowers in my opinion the world has ever seen and to stand alongside them on the podium is a proud moment for me."
Alan Campbell showed outstanding determination to hold onto third place when it could so easily have been snatched from his grasp.
I will never experience this again in my lifetime, it is so unique and special and I'm so proud to have bronze
Afterwards he even needed help walking to the medal ceremony - who better for the job than rowing legend Sir Steve Redgrave.
"It was pain like you never imagined," the Coleraine man continued. "It was a very emotional and also the crowd where uplifting and in some ways carried me across the line.
Campbell's bronze is the first medal for Team GB in the single sculls event since 1928.
He has been part of the last two Olympic Games, in Beijing he finished fifth and that was just after knee surgery.
Since then the 27-year-old's goal has been to win a medal in London and his dedication went to the extent of training all over the Christmas Holidays.
Last year, UTV caught up with Alan when he flew home for Christmas - but being home for the holidays didn't mean there was any let-up in his gruelling training regime.
In fact, even on Christmas Day, he was running up steep sand dunes at Portrush Strand beach to a regime inspired by the Rocky movies.
And, as reporter Gareth Wilkinson discovered when he took up the Olympian's challenge, that's a tough test for anyone.
For Alan though, it's simply a question of being dedicated to his sport and doing what he has to do to ensure he's in top shape to represent Northern Ireland as part of Team GB.
And as he prepared for the race on Friday he admitted listening to Christmas music to take his mind back to that excruciating boot camp.
Lanes one to three were seen as a disadvantage due to crosswinds but that didn't stop Campbell making an early impact.
By the half way stage he was just about in third place and the crowds lining the banks for the final quarter played their part in helping him hold on.
"I've been, hugely lifted by the messages of support from NI and it's almost too much, I really do feel proud to have represent my wee part of the country," he said.
"I'm so proud to be part of what the Chambers brothers did as well, with their silver, we have a bronze, we need one of the boys coming through now to go and get the gold."
Alan's proud mother Jennifer was amongst around 50 family and friends who had travelled from Coleraine to roar him on to success.
His mother, Jennifer Campbell, said: "I was shouting from about 400 metres to go.
"This is what Alan had hoped for and he told us he could do this, so we had enough faith in him. It means a lot to Alan because he's such a Northern Ireland guy. He's so passionate about his home town and they're so passionate about him."
At this stage of the London Games, Coleraine's two silvers and one bronze add up to more medals the likes of Sweden, Spain, and India - a truly Olympian effort from the North Coast town with a population of just over 24,000 people.