"Sam was cleaning up as soon as he started riding. He was born to ride a bike. I was forever and still am chasing his wheel," said Mitchell. "We are best mates. I'm best man at his upcoming wedding. We have grown up together, we have grown into this environment together and we have spent a lot of moments in our lives together."
Mitchell said he wanted to take some time out after the Tokyo Olympics to contemplate if he wanted to continue through to this year's Commonwealth Games and beyond, or to finish. And if so, what would he do with his life.
"I also wanted to decompress from that five-year campaign and work out what is next rather than just stop riding my bike. It was a matter of figuring out what I am good at other than riding a bike fast and take the time to contemplate that.
"After all, high performance sport is all-encompassing. You give it all of your attention and everything you have. And I have dedicated myself to being the best I can be. But the time is now right for me to move on.
"I have shared in some amazing times and experiences, got to ride and train with and against some outstanding people, had great coaching and support, and got to compete and travel to all corners of the globe.
"I have been fortunate to call my passion my job for many years. I owe all of my experiences to the support Cycling New Zealand has shown me.
"My family and friends have been by my side every step of the way. I am leaving our sport as much the bright-eyed boy as when I started, and will celebrate in every future success our kiwi athletes have."
He is excited at his next move in a completely new direction, yet to be announced.