"Not everyone is that fortunate. I have learned to appreciate life a lot more and to be grateful for what I have," the actor said.
Court records show Rolleston was driving at a speed considered "dangerous to the public" and caused injury to Kaleb Maxwell, who was a passenger in the vehicle, on July 26, 2016.
Rolleston was taken to Waikato Hospital's Intensive Care Unit where he remained for nearly a month.
Maxwell was also seriously injured in the crash.
Rolleston said since the accident, alongside his rehabilitation, he has been working in the community for youth recognition of the importance of road safety.
"My hope is that this work, and the coverage of my story, will get other young people to take care on the roads for their own benefit and that of their friends and family.
"Just cause we are young, we are not indestructible, and in one stupid moment, there can be huge damage. I learned this the hard way but thankfully have a second chance.
"We all need to recognise this, every time, and for every second we are in a vehicle. I am grateful to my family, friends and the wider community for the incredible ongoing support that I have received.
"A part of me feels that I don't deserve it after letting everyone down by my act of stupidity that night.
"However, I have learnt and it is that understanding and support that strengthens my resolve to be the best I can be and to lead a positive, safe and responsible example for others in the future. I am grateful just to have the opportunity."
He was remanded at large until his sentencing at the Opotiki District Court on May 11.
The maximum penalties for a dangerous driving conviction are a $20,000 fine and five years in jail.
