He taught at the Escuela Normal de Maestros in Barcelona and was a member of the Partido Radical opposed to the Catalan Statute. In the US he published a book on the crimes of the Franco regime. Under the pseudonym “Xan Calquera”, he broadcasted a pro-Republican radio program, although he was not part of the Sociedades Hispanas Confederadas. In 1938 he was editor-in-chief of the New York newspaper La Voz. He maintained an enmity with Castelao for political reasons that had begun in Spain, when Castelao accused the leader of the Partido Radical, Emiliano Iglesias (from Ponteareas), of electoral irregularities. According to Emilio González López, Poza Juncal sent anonymous letters to Castelao.
After the war he taught Spanish at the Eastman School of Languages and Business (1940), and set up a private school, Poza Institute of Languages and Business (1941), where he taught Spanish and prepared for secretarial, stenography and typing. From 1943 he was also a professor at Brooklyn College in New York (Fontes: Emilio González López, Castelao, propagandista da República en Norteamérica (2000); Consello da Cultura Galega, “Repertorio biobibliográfico do exilio galego”).