Media reports said English Premier League side City, who became the world's richest club after they were taken over by the Abu Dhabi United Group in September, had bid 110 million euros ($145 million) for one of soccer's most-coveted players.
"At the moment I don't want to change anything," Kaka told AC Milan's television channel late on Monday.
"All the messages that I received said to choose with the heart and I think in the end that has been the decision. It is absolutely not about money."
Kaka, courted by Real Madrid last year and also linked with Chelsea in the media, played in Milan's 1-0 home win over Fiorentina on Saturday and was overwhelmed by the response of the crowd who unfurled countless banners asking him to stay.
"Saturday was something extraordinary. It was very emotional," he said. "I'm very, very happy."
Milan owner Silvio Berlusconi, who lost striker Andriy Shevchenko to Chelsea under similar circumstances in 2006, hailed the 26-year-old for putting football prowess before wealth.
City are 11th in the Premier League and have had little success in England or Europe.
"Money is not everything for Kaka, there are things more important than money. We are happy," the Italian Prime Minister told Italian television.
"We offered the player the chance to consider the offer... but he has higher values."
City said an agreement with the seven-times European champions had not been possible.
"Following a meeting in Milan today (Monday), the club felt that it was unlikely that the two parties could reach common ground for an agreement," a statement said.
"The discussions reached only a preliminary stage and the player was not involved at any time."
AMBITIOUS CITY
City executive chairman Garry Cook added: "Whilst Manchester City Football Club has an obvious interest in world class players of the quality of Kaka, we owe it to our fans that such a transfer must work on every level; commercially, financially, in terms of results on the field and within Manchester City's broader community."
Cheering fans gathered outside Kaka's central Milan home once the news started to emerge. Rossoneri supporters had earlier protested against the sale in the pouring rain outside the club's city centre headquarters, blocking traffic.
Milan chief executive Adriano Galliani met City officials last Tuesday to first discuss their interest in the 2007 Ballon d'Or winner and FIFA world player of the year.
Ambitious City sounded bullish about their chances of signing him and at the weekend Berlusconi said it would be tough to hang on to the player given the sums being discussed.
City signed fellow Brazilian Robinho from Real Madrid in the previous window and did have some success in the transfer market earlier in the day.
They signed Craig Bellamy from West Ham United while Dutch international midfielder Nigel De Jong has also been given permission to speak to City about a move from Hamburg SV.
CITY FANS! Ch
