Having come to police attention, he abandoned his native city to study Romance Philology in Seville, returning eventually to the University of Deusto, where he received his doctorate.

[4] In 1980, he affiliated himself with the Communist Party of Spain during its process of unification with Euskadiko Ezkerra (EE), which would give rise to a new social-democratic group that actively rejected the use of violence.

He left it in 1986, disappointed when EE did not form an alliance with the Spanish Socialist Workers' Party (PSOE) after the Basque Autonomous Community elections of 1986.

Later, he declared in his memoirs that he did so spurred by "ethical imperatives" as a result of the attack by the radical separatist "Mendeku" group against the "Casa del Pueblo" (PSOE local chapter) in Portugalete.

Juaristi converted to Judaism[7] for reasons more personal than religious: El judaísmo para mí no es exactamente una religión, sino más bien una visión ética del mundo[8] ("Judaism is for me not exactly a religion, but rather an ethical view of the world")Advertí que yo me consideraba un judío no religioso, si tal cosa es posible.

His poetry frequently evokes the mood of the Bilbao of his childhood and youth, and its tone is disillusioned, bitter, urban and intelligent.