After qualifying in philosophy, Paniagua received a doctorate in history with a thesis on Spanish anarchism.
He is a teacher of Social History and Political thought at UNED (Spain).
His early political activity was with the Spanish Communist organisation (Bandera Roja.
He was Director General of Secondary Education in the Valencian regional administration from 1983-1986.
As first substitute, he returned to the Congress one year later on 10 June 1994, replacing Vicente Albero.