He began his political life as a union leader and participated intensely in the strikes of the 1980s during the military dictatorship. He presided over the São Paulo Banker's Union from 1984 to 1986. He was arrested four times by the military regime's Department for Political and Social Order ("Departamento de Ordem Política e Social" or DOPS")." He was also one of the founders of the Brazilian Workers' Party (PT) and the Unified Worker's Centre (CUT), in addition to being one of its leaders (he was the Workers' party's National President from 1988 to 1990).