Goals from Joleon Lescott and substitute Edin Dzeko either side of half-time were enough to overcome Bolton at the Reebok Stadium.
It was just the result City were looking for and capped a superb season with the FA Cup now installed in their trophy cabinet.
City were forced to make a late change with Pablo Zabaleta replacing Micah Richards who was apparently injured in the warm-up.
They almost made the breakthrough in the fourth minute when David Silva cut the ball back into the path of Carlos Tevez. The Argentina striker rattled in a shot from close range but it was blocked by Zat Knight.
Bolton responded five minutes later with Vincent Kompany being pulled back for a challenge on Daniel Sturridge. Lee-chung Yong picked out Gary Cahill only for the defender to send the header wide.
The home side kept up the pressure when Kevin Davies saw his effort shave the post after a corner from Lee.
City were again forced on the back foot in the 19th minute when Sturridge released Galatasaray-bound Johan Elmander and he thumped in a shot that was superbly turned over the bar by goalkeeper Joe Hart.
Hart then reacted quickly to turn away a header from Kevin Davies in a good spell of pressure by the home side.
However, City should have taken the lead in the 33rd minute when Dedryck Boyata delivered a superb ball to the back post.
Gareth Barry found himself unmarked but only succeeded in sending his header against the bar.
City suddenly had the momentum and Carlos Tevez saw his shot blocked after a galloping run by Yaya Toure in the 38th minute.
The ball broke to Silva only six yards out but he sent his shot high into the crowd.
The visitors eventually made the breakthrough in the 43rd minute from a set piece. Adam Johnson swung in a corner and Lescott delivered a looping header over goalkeeper Jussi Jaaskelainen and into the net.
Sturridge saw his effort go the wrong side of the post in the 51st minute but back came City.
Toure and Silva linked up only for the Spanish forward to find Jaaskelainen's body with his shot.
Mancini made his first change in the 61st minute with Dzeko replacing Adam Johnson. The Bosnian made an instant impact putting City 2-0 ahead a minute later after Barry played the ball into the area.
Gary Cahill got in a terrible muddle and failed to make a routine clearance, leaving Dzeko to smash the ball home for only his second league goal since arriving from Wolfsburg in January.
City maintained the momentum and Tevez wriggled his way into the area but his shot was blocked.
Elmander was given a round of applause by the home fans when he came off in the 71st minute with Tamir Cohen given a run-out.
Bolton were struggling to get any kind of a foothold in the game and found themselves reduced to 10 men four minutes from time.
Former City striker Sturridge, on loan from Chelsea, was given a straight red card for a challenge on Dzeko.
It completed a miserable day for the home side who slumped to a fifth successive defeat after a bright start to the campaign.