In 1995 he became a secretary in the Juventud Peronista in the Consejo del Partido Justicialista (Justicialist Party Council) in the district of La Matanza.

On 24 October 1999 he was elected as councillor from the party, and chosen by his peers as the president of the Honorable Concejo Deliberante (part of the legislature), a position he would hold from 2002 to 2003, and then again, after being re-elected from 2003 to 2005.

The government of Espinoza as mayor of La Matanza was marked by the start of a decentralization policy, dividing the territory in communes.

[3] He also founded the Centro de Operaciones Municipales (COM) (District Operations Center) and the Local Patrol in response to a growing request from the population for security improvements.

[5] In September 2009, as part of a charity dinner held once a year by the Obra del Padre Mario Pantaleo, Espinoza got the Solidarity Hand for his "Work for the wealth of the community".