Over the course of the following more than two days they firmly observed the kidney, running various checks and tests.
Lead specialist Dr Robert Montgomery told the BBC's World Tonight program: "We noticed a kidney that fundamentally worked like a human kidney relocate, that seemed, by all accounts, to be viable in however much it did every one of the things that an ordinary human kidney would do.
"It worked ordinarily, and didn't give off an impression of being going through dismissal."
The specialists relocated a touch of the pig's thymus organ as well, alongside the kidney. They figure this organ may assist with halting the human body dismissing the kidney in the long haul by wiping up any wanderer safe cells that may somehow or another battle the pig tissue.
A heart relocate beneficiary himself, Dr Montgomery says there is a pressing requirement for discovering more organs for individuals on holding up records, despite the fact that he recognizes his work is disputable.
"The conventional worldview that somebody needs beyond words another person to live is never going to keep up.
"I surely comprehend the worry and what I would say is that right now around 40% of patients who are hanging tight for a transfer pass on before they get one.
"We use pigs as a wellspring of food, we use pigs for therapeutic uses - for valves, for prescription. I believe it isn't so unique."
He said it was still early examination and more investigations were required, however added: "It gives us, I think, new certainty that it will be OK to move this into the facility."
The group of the beneficiary, who had needed to be an organ contributor, gave consent for the medical procedure to go on.
US controller the FDA has supported the utilization of the hereditarily altered pig organs for this kind of exploration use.
Dr Montgomery accepts that inside 10 years, other pig organs - hearts, lung and livers - could be given to people requiring transfers.
Dr Maryam Khosravi, a kidney and escalated care specialist who works for the NHS in the UK, said: "Creature to human transplantation has been something that we have read throughout recent decades, and it's truly fascinating to see this gathering move forward."
On the morals, she said: "on the grounds that we can doesn't mean we ought to. I think the local area everywhere needs to address these inquiries."
A representative for NHS Blood and Transplant, said coordinating with more human givers stayed the need for the time being: "There is still some best approach before transfers of this sort become a regular reality.
"While scientists and clinicians keep on putting forth a valiant effort to work on the opportunities for relocate patients, we actually need everybody to settle on their organ gift choice and let their family in on what they need to occur if organ gift turns into a chance."