He was born in Barcelona to Juan de Dios Trías y Giró and Rosa Bes Baguer. Dos de sus hermanos, Juan de Dios and Frederic, were also jurists. He married Teresa Borrás de Quadras, with whom he had three children.

He studied at Instituto de Barcelona and graduated in Law from Universidad de Barcelona on 22nd June 1912, obtaining his doctorate a year later from Universidad Central de Madrid.

He was professor in International Law at Universidad de Barcelona in 1916. He was given many leaves due to him being elected Parliamentary Deputy. He was elected Dean of the Faculty of Law of Universidad de Barcelona in 1936. In 1960, he asked for a voluntary leave to act as Director of the International Law Department of the Ministry for Foreign Affairs. He retired in 1960.

In 1936, his professorship was taken away by the Republican government, but he was admitted again in 1939. During the Civil War, he worked as an expert in International Relations for the national party. During Franco's regime, he was director of the Ministry for Foreign Affairs Council.

He was also a correspondent editor in Spain for the Journal de Droit International de París desde 1918 and a professor at La Haya International Law Academy. He was member of the International Law Institute, member of the Real Academia de Ciencias Morales y Políticas since 1947, and member and president of the Real Academia de Legislación y Jurisprudencia of Catalonia. Furthermore, he was a collaborator of the journals Revista General de Legislación y Jurisprudencia and Revista Jurídica de Cataluña.

He was also Parliamentary Deputy for Seu de Urgell in 1918 and 1919; for Granollers in 1923; for Barcelona in 1933 and 1936; and for the Catalan Parliament as a member of the Regionalist League in 1932.