He was also in the Argentina team which finished as runners-up to Brazil at the Copa America in July and helped Boca Juniors win the Copa Sudamericana in December in his last game for the club before moving to Corinthians.
Tevez, who received 76 votes, was signed by the Brazilian club at the start of this month in a $18 million move, a record deal between two South American clubs.
Only former Colombia midfielder Carlos Valderrama had previously won the award twice.
River Plate midfielder Javier Mascherano, another 20-year-old Argentine, was second with 56 votes after an outstanding season in which he established himself as a regular for his national team.
Third place was shared between Brazil and Santos forward Robinho and Argentina midfielder Luis Gonzalez, who also plays for River. Both received 37 votes.
The award, the most respected in the region, has been given every year since 1986 and is based on a poll of around 400 journalists.
Players and coaches have to be based in Latin America for at least part of the year to be eligible.
Previous winners include Brazil's Romario and Cafu.