An attacking midfielder, he started his career with São Paulo, joining their youth academy in 1994, then signing with the club as a professional in 2001. He remained there for a little over two seasons, making 59 league appearances and scoring 23 goals. That attracted the interest of AC Milan, who signed him in the summer of 2003 for a transfer fee of €8.5 million.
An accomplished provider of assists in addition to goals, Kaká helped Milan to the league title in his first season there. In 2005, they reached the Champions League final, but lost to Liverpool. Both teams returned to the final in 2007, with Milan winning 2-1. Kaká was the tournament's top scorer. Later that year, Milan won the Club World Cup and Kaká claimed the Ballon d'Or and the World Footballer of the Year award.
In the summer of 2009, he moved to Real Madrid for a transfer fee of €68.5 million, an amount that, at the time, was the second-highest in history after the €76 million Real Madrid paid for Zinedine Zidane in 2001. (It dropped to third after the club signed Cristiano Ronaldo for €94 million in later in the summer of 2009).
At Madrid, has battled through injuries, but has still made made over 80 appearances there and helped them win the league title in 2012.