City and Lazio had agreed to on a fee last week, with the interim spent securing work permits, agreeing to personal terms, and completing physical examinations. On Saturday, those steps were completed, Kolarov was able to complete a five-year contract to move to Manchester.
Kolarov spent the last half of the Serie A season being linked to the likes of Internazionale and Juventus, and of late Liverpool had been thought interested in acquiring the left-back. However, the 24-year-old now moves to Eastlands, becoming Manchester City's fourth major signing of the summer, having already acquired Jerome Boateng, David Silva, and Yaya Touré.
"I want two top-class players for each position," said the Italian.
"I first saw Kolarov in his Lazio debut back in 2007. I have watched him a lot since then and so have the Manchester City scouts.
"His attacking capability is very good. He is fast and can shoot with power and accuracy.
"He also has the ability to play in numerous positions and is very good in midfield."
Kolarov will join his new teammates after the club completes their North American tour.