Has an unsuccessful trial at Spanish giants Barcelona in 2006 but later joins Inter Milan on loan before signing a permanent contract at the club in 2007.
After making his Serie A debut aged 17, he announces his potential with two goals against Juventus in the Italian Cup.
Wins Serie A title in his first season at the San Siro and at 18 years and 85 days becomes Inter's youngest ever goalscorer in the Champions League.
Joins former Inter manager Roberto Mancini at Premier League side Manchester City in 2010 having won three consecutive league titles in Italy.
Named man of the match as City beat Stoke City 1-0 to win the FA Cup at Wembley Stadium in 2011.
Never far from controversy and scores twice against Manchester United shortly after setting off fireworks in his bathroom. Provides the assist as Sergio Aguero scores an injury-time winning goal to give City their first league title in 44 years.
Joins AC Milan in 2013 having scored 20 goals in 54 Premier League games for City.
Leaves AC Milan, with an impressive record of 26 goals in 43 league games, to join Liverpool in August 2014. INTERNATIONAL CAREER: Makes Italy debut in 2010 against Ivory Coast, two days before his twentieth birthday.
Scores first international goal in a 2-0 win against Poland in November 2011.
Scores twice as Italy beat Germany 2-1 in the European Championship semi-final before losing to Spain in the final.
Starts all three games during Italy's disappointing 2014 World Cup campaign in which the four-time champions failed to progress past the group stage.