Supporters across the country were on the edge of their seats as the Coleraine brothers represented Team GB in the lightweight fours final at Eton Dorney.
The crew had set out for gold, and looked on course for victory as they vied with Denmark and South Africa in the closing stages of a dramatic race.
But despite a strong finish they lost out narrowly to the South African crew, crossing the line in second place to become the first brothers from NI to win Olympic medals.
The First and deputy First Ministers hailed it as an "historic achievement" for the duo and their crewmates Rob Williams and Chris Bartley.
Peter Robinson said: "I offer my sincere congratulations to Peter and Richard.
"They have worked hard for this success and while they fell just inches short of the ultimate prize, they can be very proud of their achievement on the biggest stage of all.
"Their Olympic medal is fitting and just reward for the many hours they have spent in preparation for this day and I hope that their achievement will inspire further success for Northern Ireland competitors in the days ahead."
Martin McGuinness said: "I extend my warmest congratulations to Peter and Richard and their colleagues on winning Olympic silver medals.
"As this race has shown Olympic medals are very hard won, and Peter and Richard put in a tremendous performance and while their strong finish elevated them to second they came agonisingly close to winning gold.
"They have won the praise and admiration of all."
Crowds young and old gathered at City Hall in Belfast to watch the race on the big screens and roar the Chambers brothers on as they closed in on medal success.
"People are getting really enthused by the Olympic Games and every day there is a good crowd down here but more importantly than ever today with the Coleraine brothers and their fight for a medal," said Lord Mayor Gavin Robinson.
"To reach their level in any sporting discipline I think is a real credit and for the guys to get a silver medal, well, there's only one team better than them in the world."
Sports Minister Carál Ní Chuilín offered her congratulations to the Chambers.
She hopes the brothers, who are members of the Bann Rowing Club in Coleraine, have inspired more people to take up the sport.
"To reach the final of the Olympics is an amazing achievement, one I am sure the team are rightly proud of," said the Sinn Féin minister.
"To take a silver medal in a global competition like the Olympics is no mean feat. I am sure their success will help to inspire and encourage local rowers."
SDLP East Derry MLA John Dallat has spoken of his pride in the achievement.
"It was a thrilling moment for all of us who watched the race as they Chambers boys did their bit in pushing Team GB to the finishing line, giving the other countries a real run for their money," said Mr Dallat.
"Though South Africa pipped them to the post, they embodied the Olympic spirit of sportsmanship and fair play as they fought hard for the reward they got."
The UUP's sports spokesman, Robin Swann, said the brothers success in London has been one of the highlights of the Games.
He continued: "The Olympics have really captured the imagination of the Northern Ireland public and today's race provided one of the highlights of London 2012 thus far.
"It was a thrilling race and everyone in NI is extremely proud of the Chambers brothers."
Northern Ireland will have another chance for medal success on Friday when Alan Campbell, also from Coleraine, competes in the final of the men's single sculls.