Firefighters responded to the Wall Street Bridge before donning cold-water suits and entering the river.
The swan was freed from the surrounding ice and brought to shore with the help of some special equipment and dedicated firefighters.
But when firefighters first arrived on the scene, they said they were even sure if the bird was alive.
"It was curled up, probably trying to warm itself or keep itself warm, but I did see some movement, so at that point, I was a little optimistic that we can have a good outcome," said Norwalk Fire Department Chief Jonathan Maggio.
Firefighters say the swan's feet were frozen into the river, which is completely iced over. It took crews nearly a half hour to free the bird.
"We didn't know exactly how deep it was in, so they were just cutting around, trying to see if we could do it, and we ended up just chiseling the ice away and getting its feathers and feet out," said rescuer Travis Viscount.
One complicating factor was the lack of direct access. Because of the elevation, firefighters couldn't approach from the shore and the rescue required a series of ropes.
But the swan apparently welcomed its rescuers and their heroic efforts.
"Very content...there's literally six inches from my face and it didn't seem like it wanted to bite or anything, it was just happy to be out of the ice," said Capt. Whitney King.
The animal was taken to the VCA Veterinary Referral and Emergency Center to be checked out and cared for.
During the cold snap, Norwalk firefighters have already rescued a duck and a dog, but the icy conditions also present and opportunity: to train in these exact conditions.
Firefighters say they have been using a local pond and cycling companies through, one at a time, to get everyone comfortable in the special cold weather protective suits.
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