He taught for some time in the Music Academy in Coimbra and, in 1937, went to Paris at his expenses, where he studied musicology. There he composed the first works of his musical maturity (2nd Piano Sonata, Quartet for Violin, Viola, Cello and Piano). After coming back to Portugal in 1939, Lopes Graça taught at the Academia de Amadores de Música at Lisbon. Of his production, it worth mentioning the numerous harmonizations or adaptations of popular Portuguese songs for choir or soloist, the songs for voice and piano over the poems of the most important Portuguese poets, the innumerous political songs, as well as the symphonic music, chamber music and piano music production. Lopes Graça undertook, with the Corsican ethnologist Michael Giacometti, a systematic study of Portuguese folk music, which he assimilated and used thoroughly in his musical speech. His view from the folklore is far from the regime bucolic or picturesque view, rather strengthening the hard dimensions of rural life.