Bermúdez was born in Gijón, Asturias. He founded an art academy at Seville, and was given responsibility to order the Archivo General de Indias or the repository of documents relating to the Colonies. He later made secretary of the Council for Indian Affairs in Madrid, a post later lost. He put himself in the service of the statesman and author Jovellanos and wrote his master's biography; Jovellanos then helped pay for his artistic studies and placed him in a government position. He is best known as the author of the Diccionario Historico, a biographical dictionary of the principal artists of Spain. He was also a friend of Goya.