Playing as an midfielder in the classic "Enganche" role, he spent most of his career playing for Boca Juniors, where he won ten titles, including three Copa Libertadores de América and one Intercontinental Cup, where they defeated Real Madrid 2-1. In 2002 he was transferred to FC Barcelona, but his time at the club was short due to his fights with the team's coach, Louis Van Gaal. Román would end up signing at Villareal, where he would have his most important moments in Europe, achieving a third position in the league and reaching the semifinals of the Champions League for the first time in the history of the "S"ubmarino Amarillo"". Finally, in 2007 he would return to Boca Juniors, where he would get the Copa Libertadores again, being the top scorer and MVP of the competition. In his third cycle with the "Xeneize", he would win two more league titles and an Copa Argentina, and he would resign from the club twice; in 2012 after losing the final of the Copa Libertadores and in 2014 after the club president decided not to renew his contract.