Andy Clewes had the transplant in Manchester after his friend Helen Crowther agreed to become a donor.
The 46-year-old suffered chronic kidney disease since birth and was on the verge of needing dialysis treatment.
Mr Clewes and Ms Crowther, 45, are now planning "a curry and a few beers" to celebrate the successful procedure, which was carried out in January.
"I've just got so much more energy now," Mr Clewes, a radio DJ from Crewe, Cheshire, said.
"There was a time when I could sleep 23-hour days, but now I struggle to get myself off to bed.
"It's hard to describe how it feels. Every now and then you remember how lucky you are to have your mate's kidney."
Mr Clewes said the pair would like to get involved in charity work to support others in need of transplants - and may even take on an extreme challenge.
"There are a few organisations who do skydives and things like that, and I've never done something like that before," he said.
"I think it's something I'd like to look at once I'm fully recovered."
Although his strength has returned, Mr Clewes will continue to need regular check-ups and medication to prevent his body rejecting the organ.
But he added: "I'm feeling great. I'm exercising. It's really a life-changing step and I don't want to let Helen down."
Ms Crowther, a charity worker from Runcorn, met her friend at a fundraising event in 2006 and later became "best woman" at his wedding.
She said: "I think Andy's a bit worried he might now take on some of my characteristics.
"I think his wife might like that as he might start tidying up around the house a bit more.
"We met up about four weeks after the operation and just fell back into normal every day chatting really.
"We have plans to celebrate properly and knowing Andy it will probably just be a few beers and curry."
About 3,000 people have kidney transplants each year in the UK and about a third of these are from living donors.
You can find more information on the NHS Organ Donation website.

Reports of the white substance on beaches started appearing last October after one dog died from eating it on a Cornwall beach.
Since then the substance has been seen as far away as south Devon.
Bad weather has washed in large boulder-like clumps of palm oil at Perranporth.
Dog owners are being warned to keep their pets away from the white waxy substance, which smells like diesel.
Chris Gardner, of St Clements Vets in Truro, said: "We have been lucky we haven't lost any dogs through them eating palm oil.
"We were seeing dogs on a daily basis two weeks ago. Then it went quiet in the storms, probably because there weren't so many people on the beaches.
"But we had a dog brought in yesterday from Porthtowan. It is still an ongoing issue."
Reports of the substance had come from Porthtowan and Gwithian.
"I have seen 2ft-diameter lumps," said Mr Gardner. "It has a strong diesel smell, so if you smell it on your dog get advice immediately."
Vets treat poisoned dogs by making them vomit and giving them liquid charcoal to absorb the substance.
The substance was analysed by the Maritime and Coastguard Agency.
Palm oil has a wide variety of uses and is found in food, soaps and shampoos, and biofuels.
The source has yet to be identified.
A man who was given a kidney by his best friend says he feels "100% better" and is considering a charity skydive.
[NEXT_CONCEPT]
Cornwall vets say they have been seeing a dog every day that has been poisoned by palm oil washed up on beaches.