A newborn baby, who lived for less than two hours, became Britain's youngest-ever organ donor last year.
Doctors at the University Hospital of Wales, Cardiff, carried out the pioneering surgery three minutes after Teddy Houlston died on April 22.
His kidneys were then used to save an adult's life in Leeds.
His parents, Mike Houlston and Jess Evans, from Cardiff, say they want people to know his story and see his face, saying: "We are so proud of him".
In an interview with told the Daily Mirror, Mr Houlston said: "He lived and died a hero. It's impossible to explain how proud we are of him."
Ms Evans was carrying twins when she was told - 12 weeks into her pregnancy - that one was fatally ill.
Teddy had anencephaly, a rare and lethal abnormality which prevents the brain and skull from developing.
Babies with the condition either die in the womb, are stillborn or live for just seconds, minutes or hours after birth.
Ms Evans told the Mirror that the news of Teddy's condition was "soul-destroying".
Though doctors offered the couple the option of an abortion, Ms Evans said: "We thought that even if we had a moment with him, or 10 minutes, or an hour, that time was the most precious thing that we would ever experience."
As they continued with the pregnancy, the couple decided that they wanted to donate their baby's organs.
Ms Evans said: "Organ donation was something I've always felt quite strongly about ever since I was a child."
In an interview with the BBC, Mr Houlston said they were initially told a transplant was not possible because it had never been done before.
But he said hearing the news that the transplant from Teddy had gone to plan had left them with a feeling of joy, saying: "We never doubted him".
"He is still very much a part of our family today, we talk of him every day, our children talk of him, our families do, we always remember him, he is with us all the time," Ms Evans added.
The success of the transplant "helped us grieve", she said, adding: "Knowing that he was able to do such good, more good than most of us will ever do in our lifetime - it is just overwhelming how proud we are of him."
Retrieving organs from children for transplant is rare, it is particularly unusual from newborn babies - and unheard of in those with anencephaly.
Yet his kidneys would have been fully functional in the womb.
Angharad Griffiths, a specialist nurse from NHS Blood and Transplant who helped complete the transplant, said told BBC Radio 4's Today programme she had "every belief" that a similar transplant could be successfully carried out in the future.
She said the transplant had been "challenging", particularly as they did not know if Teddy would be born alive.
Her team monitored Teddy throughout his short life, before performing the transplant minutes after he died.
Being present throughout Teddy's life was "a privilege", she said, saying his life was "an hour-and-a-half of pure joy".
"There was some sadness in the room naturally, [his parents] knew they were going to lose their baby, they knew he would pass away, but they were overjoyed that he had been born alive and they had those precious minutes with him and they spent those precious minutes enjoying him and his life," she added.
By Philippa Roxby, health reporter, BBC News website
The process of matching a donor's organs to a recipient on the transplant waiting list is a complex one.
Depending on the organs donated, the needs of the people waiting, their tissue type, overall health and location, the organs are offered to the most appropriate patient on the waiting list.
In this case, Teddy's kidneys - which were unaffected by the rare brain disease he had - will be able to grow inside another living body, making them suitable for donation to an adult, as well as a small baby.
Teddy lived for 100 minutes after he was born. After he died, doctors would have moved quickly to perform the rare and intricate operation to remove his kidneys and use them to save another life.
His case puts the focus back on neo-natal organ donation as a way of increasing the number of organ donors in the future.
There are currently around 7,000 patients on the organ transplant waiting list in the UK.
The Mirror said that the family visited Teddy's grave on Wednesday - on what would have been his first birthday - with his surviving twin, Noah.
Ms Evans said: "Although he wasn't with us very long, and we brought him into the world knowing there was no hope of a life for him, we are incredibly proud of his heroism."
"We hope Teddy's story will inspire families who find themselves in the position of losing a child."
The couple are encouraging anyone who is not on the NHS Organ Donor Register to sign up.
They are also raising money for the charity 2 Wish Upon a Star, which aims to improve bereavement services for parents who lose babies or children.
Earlier this year, doctors at the Imperial College NHS Trust in London revealed that a six-day-old baby girl's kidneys and liver cells had been given to two separate recipients after her heart stopped beating.
At the time, it had been thought she was the youngest organ donor in the UK.