Smith was dumped from the All Blacks in October last year after an indiscretion with a woman in a toilet at Christchurch Airport in September.
He had not spoken publicly about the incident until yesterday when he fronted the media as he prepares to play his 100th game for the Highlanders.
``I just think it was a huge mistake by me and just the affect it had on me and my performance. Just the way it hurt me and my family and my partner,'' he said.
``It was just a really tough time. I probably should have put rugby on the backburner for a while. But I have learnt a lot and we are past that now.
``I think a lot of positives have come from that incident both on and off field. Now I feel as though it is coming out in my game now.''
Smith missed a couple of tests but did go on the end-of-year tour to the northern hemisphere. But he was obviously struggling - the zip was gone from his game.
``I have had heaps of help. I've done a lot of counselling and things. But importantly from things like that you learn who your real friends are. It puts everything in perspective.
``A lot of positives have come for me - in my life and family - and I'm hoping I can turn a page on that. I am in a really good place now, both on and off the field and just loving how life is.''
Smith said his urge to get back to playing came around Christmas and showed the hunger was still there.
``Usually you need that whole two months to come back and play.
``But I remember thinking about Christmas time, I was pretty excited about getting back and playing for the Highlanders again. Mentally, I feel good and physically I feel good.
``Sometimes when you come back, you come beat up and mentally fatigued. I had fixed a lot of things off the field and I was up for the season.``
He said he had jeopardised his role in the All Black jersey with his indiscretion and it was up to him to get it back.