The 25-year-old winger completed a big-money move to Sunderland from the Etihad Stadium on Friday after finding himself surplus to Roberto Mancini's requirements.
Johnson could have signed for the Black Cats back during the 2010 winter transfer window with then manager Steve Bruce hot on his trail, but opted instead for the riches and trophy prospects at City.
Johnson said: "I had the choice of going to Sunderland or City, and I probably made the right decision with the medals and the experience I have had.
"Looking back, I would probably do it again - I suppose any young lad would in my situation then. But it's worked out now that I am here."
Martin O'Neill beat off competition from a series of Premier League rivals to bring former Middlesbrough winger Johnson back to the north-east and end what had become a frustrating period of his career.
He was far from guaranteed a place in Mancini's starting line-up and with the Italian indicating that the situation was unlikely to improve, he decided to cut his losses.
Johnson admits he will look back on his time at City with mixed feelings, but his spell with the club will also include some big highlights.
He said: "You can always look back and think. It was a slightly disappointing end, but I won the Premier League, FA Cup and the Community Shield and played in the Champions League, so it wasn't all bad.
"But it was a little bit disappointing I didn't play as much as I was capable of.
I owed it to myself to go and play football again and enjoy playing."
Johnson made his debut for his new club in Tuesday night's 2-0 Capital Cup win over League Two Morecambe, in which he set up James McClean for both goals, and will hope for a first Premier League appearance at Swansea on Saturday.