The striker, whose unhappiness was reported by Sportsmail, scored two penalties and a tap-in as Roberto Mancini's side thrashed Villa 4-0, putting Gerard Houllier's five-month reign in further jeopardy.
Super Mario: A hint of a smile from Balotelli as he celebrates his hat trick against Aston Villa.
City overtook their neighbours at the top of the table, only for Manchester United to regain the top spot when they drew 1-1 at Birmingham.
After his treble, Balotelli denied being homesick, saying: 'I am happy, even when I don't smile. I feel a striker has to score. It is my job. That is why I don't smile.
Happy days: Roberto Mancini enjoys a joke with his Villa counterpart Gerard Houllier
'I am very happy here, even if the journalists in Italy say I want to go to Milan. I am working hard in training and I want to be an important man for this team.'
Mancini compared Balotelli's problems at City with those encountered by Cristiano Ronaldo when he came to England. Asked afterwards what he would like for the new year, the City manager said jokingly: 'A smile from Mario. That would be great.
'Maybe it could be that he is homesick because he is only 20 years old and it's normal to miss your family at that age.
'My assistant Brian Kidd has told me that Ronaldo had Mario's same problems when he arrived at Manchester United (from Sporting Lisbon) and he needed time to adjust.
'Mario is learning. He has to understand this country and this football before he can give his best. He is working on it, and knows he has to do more for himself as well as for the team.
'When he has assimilated this concept, and made use of his superior qualities, he'll become an important player.'
Manchester City 4 Aston Villa 0: Miserable Mario bags a hat-trick but insists: I'm not homesickMancini admits Balotelli is homesick and confirms interest in Dzeko and Luiz Roque and a hard place: Santa Cruz demands long-term, not Lazio loanMANCHESTER CITY FC