Dominguez' professional football career spanned 19 years during which he played for teams in Argentina, Brazil and Mexico, winning titles with all but one.

At an early age he was purchased by a third-party and loaned to Talleres de Córdoba along with his teammate Maxi Rodríguez, but he was never authorized to play for the club and returned to Newell's shortly after.

[1] He played as a defensive midfielder until 2004, when he was moved to centre back by coach Américo Gallego and he captained the team that won the 2004 Apertura tournament, thus breaking the club's 12-year title drought.

[2] After winning the league championship with Newell's, Domínguez was purchased by third-party Media Sports Investment for $2.5 million (US),[3] that loaned him along with fellow Argentine players Carlos Tevez and Javier Mascherano to Brazilian side SC Corinthians.

During the 2007 January transfer window, Domínguez returned to Argentina to play for Estudiantes de La Plata, under Diego Simeone's coaching.

[8] On 31 August 2009 Domínguez was called up by coach Diego Maradona for the Argentina national team, along fellow Vélez Sársfield teammates Nicolás Otamendi and Emiliano Papa.

Domínguez was later called by coach Alejandro Sabella for the 2011 and 2012 editions of the friendly competition Superclásico de las Américas, in which he captained the national team.