Bernardino Machado was born in Rio de Janeiro, Brazil, the son of António Luís Machado Guimarães (1820-1882), 1st Baron of Joane and a nobleman of the royal household, a rich merchant raised to the nobility, and his second wife Praxedes de Sousa Guimarães.
In Porto in January 1882 he married Elisa Dantas Gonçalves Pereira (Rio de Janeiro, Rio de Janeiro, 15 December 1865 - 21 April 1942), by whom he had sixteen children.