What was harder was the doctors' recommendation he would need six to nine weeks to recover.
That did not fit with the Wanaka Rookie Academy instructor's peripatetic lifestyle.
Richie wants to return to Vancouver and his partner, Kenrae Dorsey, at the end of next month and be on the slopes of the Whistler skifield by mid-December.
So he has embarked on an intensive training programme to get fitter than ever to speed up his recovery.
On October 11, he completed a 1026km trip with cycling companion Christina McGrath around the lower South Island in eight and a-half days.
"I've known since May. It was a pretty easy decision to make and the more I found out about it, the easier it was," Richie said. .
The recipe for a good recovery was eating well, drinking less and keeping active, he said.
"I don't have to be fit. I wanted to be.
"I wanted to go through the recovery part of the operation as fast as possible.
"To help that, I know I have to be in good shape."
His very grateful father, Rob (57), says he is proud of his son's dedication to healthy lifestyles and fitness, as well as his decision to give a life-saving kidney.
"I think that's a brave decision, if you ask me."
Rob Johnston has been unwell since last November and has been receiving peritoneal dialysis four times a day for the last three months after his kidneys failed.
He and his wife, Janey, operate a bed and breakfast, are regular community volunteers and enjoy an active and healthy lifestyle.
But in recent months he has not been able to keep up with his wife and joked that his son's kidney would probably help him in that regard.
He was also expecting his diet to change to match his son's likes and dislikes.
"Apparently, your tastebuds change, I've been told on a couple of occasions.
"But, fortunately, there's not a lot of difference [between likes and dislikes]," he said.
Richie said he was not expecting major lifestyle change after donating his organ because he intended to be fit for life.
"Our bodies are precious. They shouldn't get unnecessary abuse.
"I will still drink and have a good time but it won't be excessive," he said.
The men said they were keen to talk about the operation to educate people about organ donation.
Richie will be creating a personal WordPress blog about the operation, which will be done in Christchurch Hospital, and his recovery.
His father said he expected a swifter recovery than his son because the young, healthy kidney would enable his body to start healing immediately.
His son's recovery would take longer because his body had to adapt to losing a healthy organ.
Rob and Janey Johnston are moving to Dunedin for a year to be close to medical services but intend to return to Wanaka.