While working for his father's company, he developed an interest in English literature, which he wrote about in the Catalan newspaper La Publicitat.
He opened the Dolphin Bookshop just off Charing Cross Road in London, specialising in Spanish and Latin American books and manuscripts.
These included textbooks and literary studies, and translations of Miguel de Unamuno, Luis Cernuda, Juan Ramón Jiménez and Pablo Neruda.
In the 1950s, Penguin Books asked him to make prose translations of Lorca's poems; this bilingual edition was a significant influence on several generations of poets and schoolchildren.
In 1948, he became a naturalised British citizen, but although he officially changed his name to John Gili, his friends and family continued to call him Joan.