John Cassell, 36, from Redcar was inspired to donate an organ after seeing a tweet from a little girl who needed a life saving transplant.
At that point he didn't know anything about kidney disease or about giving kidneys away.
It prompted him to research organ donation, and he discovered that it's possible for most people to give away a kidney, after plenty of medical tests. He started those a year ago, which also included psychological evaluations.
He shortly got a call to say a 30-year-old man - who had been very hard to find a match for - was ready, and he went into hospital.
John said recovery was quite quick and the NHS were able to support him financially while he took time off work following the operation.
All John knows it that the operation was a success, and lives with the knowledge that he's given the ultimate gift to someone he'll probably never meet.