He studied law in Santiago and political science in Berlin. He was Secretary General of the Ministry of State and a delegate to the League of Nations. Later in Madrid he received his doctorate and started a diplomatic career. In December 1933 he went to Sofia (Bulgaria) as secretary of the Spanish embassy. In 1938, after remaining in the ranks of the Republican army, he participated in the founding of the Seminario de Estudos Galegos, being director of the section of Legal, Political and Economic Studies. He also worked as a professor of Administrative Law in Santiago de Compostela.
During the Spanish Civil War he joined the Republican army and was an adviser in the design of the Statute of Autonomy of Galicia. On November 10, 1938, Álvarez del Vayo appointed him minister and later secretary general of the Ministry of State. The road to exile takes him first to New York, where he meets Castelao. Later he passed through Havana (1939-40) and together with a group of Cuban writers, Raúl Roa, Fernando Ortíz, and the Galician José Rubia Barcia, he founded the Escuela Libre de Enseñanza de La Habana. In 1940 he went to Mexico D.F. where he was a professor at the Spanish-Mexican Institute “Ruiz de Alarcón”, led by his brother-in-law Pedro Martul Rey. In the same year he went to Uruguay, where he lived for more than twenty years and came into contact with the Instituto de Cultura Gallega. In Montevideo he met with other Spanish and Jewish exiles from Germany and Czechoslovakia.
He returned to Spain in 1963 to live in Madrid. In 1974 he resumed his diplomatic career for two years, and since then devoted himself to historical research. In 2001 he received a tribute at the Ateneo de Madrid. Lois Tobío was also president of Novo Seminario de Estudios Galegos.
(Information taken directly from the “Repertorio biobibliográfico do exilio galego”, Consello da Cultura Galega, see also: Diccionario Histórico de la Traducción en España).