Coromines studied at the University of Barcelona, and started working on linguistics from an early age. At the same time, he held strongly Catalanist convictions all his life. He was forced into exile after the Spanish Civil War, eventually holding a professorship at the University of Chicago, in 1948. He returned to Catalonia later, and spent his last years working on his main works, the Dictionary and the Onomasticon.
He refused several prizes from the Spanish government, in protest at the treatment of the Catalan language and culture in Spain.
In honor of Coromines, in April 2006 the University of Chicago inaugurated the Càtedra Joan Coromines d'Estudis Catalans, a teaching chair for visiting professors of Catalan language and literature.