In the previous two campaigns, the 28-year-old had often found himself on the fringes of the starting lineup under the management of Roberto Mancini.
However, the June arrival of Manuel Pellegrini has coincided with more opportunities for the Serbian international, who has made 37 appearances so far this term.
"Last season I was thinking, because I didn't play a lot, that maybe it was a good thing for me to move," the left-back told CityTV.
"I had a couple of opportunities, but in the end I refused everything because I didn't want to go from here. I hadn't shown the people what I can do. Now, this season, I think I have shown what I can do. For me it has been a victory, personally, for myself.
"If you play regularly you can improve a lot in every game. It is difficult if you play one and then don't play three, four games. Training is one thing, the game is one thing. Playing regularly you can improve a lot."
Kolarov signed for City in 2010 from Serie A side Lazio.