He helped United win successive Premier League titles, becoming a crowd favourite as he scored 34 goals in 99 league and cup starts, and has now targeted helping bring the title to Eastlands.
"The objective is to win the league, that is what we have talked about and I'm here to make my contribution to the cause on a daily basis," he said.
"I'm here to win things and I make that pledge now to my team-mates and our fans.
"I will give everything to help City become one of the biggest and most important clubs in England - and win some trophies.
"But it is very important to remember that I am just one more player to add to the strength of the squad, one more player working with the coach and my new team-mates to help us win trophies for City."
Tevez will become one of a select band to have joined both Manchester clubs and he could re-visit his former club at the Old Trafford derby on 19 September.
"He is not only outstanding technically but he is a reliable goal scorer and someone who will contribute fully to the team ethic," Hughes added.
I have no assurances about my place and must win the respect of my team-mates as I fight to be first choice
"He gives us another exciting, attacking dimension."
Tevez scored 15 goals last season but was often on the bench for key games and was wary of not getting enough first-team football ahead of the 2010 World Cup in South Africa.
However, he rejected suggestions that he had been given guarantees of first-team football at City.
"This will be a very challenging season for me," he said. "I have no assurances about my place and must win the respect of my team-mates as I fight to be first choice.
"Then it is the World Cup next summer. I will work hard to achieve these goals."
Manchester City's summer spending so far has seen them sign striker Roque Santa Cruz from Blackburn for £18m and Aston Villa midfielder Gareth Barry for £12m.
Arsenal striker Emmanuel Adebayor is also in talks over a move to Eastlands.
But a proposed bid for Barcelona striker Samuel Eto'o fell through - even though reports suggested the club was willing to make the Cameroon international the highest-paid player in the world, earning £250,000 per week.
There have also been rumours that Chelsea captain John Terry is on Manchester City's wish-list, although Stamford Bridge boss Carlo Ancelotti insists the England defender is not for sale at any price.
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