[1] In March 2021, he was a founding member of Unir Movement, a party which joined the Broad Front (Frente Amplio; FA).

In 1999, he obtained a PhD from the Complutense University of Madrid in political sciences and sociology with a specialization in international relations.

From April 1994 to September 1996, Díaz was director of the international relations and co-operation program of the INJUV (National Youth Institute).

From October 1996 to May 2001, he was a technical officer and assistant general secretary of the Ibero-American Youth Organization (OIJ) in Madrid.

Díaz ran as a candidate for deputy in the 2017 general election for the then new 7th District which grouped the communes of Algarrobo, Cartagena, Casablanca, Concón, El Quisco, El Tabo, Easter Island, Juan Fernández, San Antonio, Santo Domingo, Valparaíso and Viña del Mar.