Nearly a year on, in between working as a coach for Great Britain's Olympic cyclists and riding himself, Grace is spending time volunteering for organ transplant support charities as well as Britain's National Health System (NHS).
He's spoken at several NHS events and took part in a 24-hour drive to raise awareness about organ donation and increase the country's donor list earlier this year.
"It's probably keeping me more busy than I'd like to be, but it's pretty hard to say no when that system saved my life," he told the Herald on Sunday.
The former top athlete, who raced for the New Zealand cycling team at the 2002 Manchester Commonwealth Games, was adjusting to a slightly slower pace of life.
Five months after surgery he was easing his way back into work and slowly rebuilding his fitness.
Then in July, he participated in the British Transplant Games in Glasgow - the first race of his life where he wasn't focused on winning.
After realising his body couldn't take the training he'd need to have a competitive edge, Grace said he shifted his expectations and decided, "I'm just going to enjoy myself".
Grace came fifth, but had already won a bigger battle - getting his vital organs back in shape after surgery.
His latest check up was six weeks ago, about the same time as the Games, and it was the first time his liver, kidneys, blood and heart markers were back in the normal range since last November.
Grace needed surgery to treat his primary sclerosing cholangitis, a condition where the liver's bile ducts become blocked.
Over time, the body slowly poisons itself as the organ stops being able to process toxins.
In the months before his surgery Grace was so unwell his skin and eyeballs turned yellow from the build up in his liver.
He was dealing with chronic pain and was bumped up the donor list after doctors told him he would die without a transplant.
It was Grace's second life-saving surgery, after being treated for bowel disease in his mid-20s.
The two conditions are known to be linked.
The liver donation was made after a patient died, and Grace has written a letter to the donor's family. He's not sure if they've read it because the letter is sent by the hospital to keep identities confidential.
But the sacrifice is never far from his mind.
"You'll be doing something and you suddenly think: 'There's a piece of someone else inside me keeping me alive and that person isn't here any more'."
Grace is most thankful for the time the transplant has given him with his wife, Erika, and daughters Madison, 11, and Cadence, 13.
"Now I've got that time I wouldn't have had before, it makes all the moments [with them] that little bit more special."
His daughters generally looked after him, although "they still rark me up every now and then. But that's their job, isn't it?"
