Marcelo was born in Brazil were he began at Mirassol a third division club in Brazil he then left for FC Tokyo in the J-League. After exceptional performances he transferred to Associação Desportiva São Caetano where he then left for Sport Club Corinthians Paulista. At Corinthians, Marcelo established himself where he excelled alongside Carlos Tévez and Javier Mascherano being dubbed the team of the year after the trio won the Championship.
He was part of the Brazilian team that played at the FIFA U-17 World Championship 2001. At that time he was with Mirassol and impressed so much that FC Tokyo signed him.
Marcelo Mattos has signed for Greek team Panathinaikos for 3 million euros on 6 July 2007 in a 4 year deal.
In July 2008, Panathinaikos acquired the 85% of the players ownership for a fee of 3 million Euros. The rest of the player's percentage belongs to his agent, Pini Zahavi.
On 26 August 2009 Corinthians announced a one year loan deal with Panathinaikos.
On 20 July 2010 he was announced as a player of Botafogo.
On 3 July 2011 he was sold to Botafogo for 1 million Euros