Junqueiro wrote highly satiric poems criticizing conservatism, romanticism, and the Church leading up to the Portuguese Revolution of 1910.

Born in Freixo de Espada à Cinta, Trás-os-Montes, Portugal to José António Junqueiro Júnior, a supply trader and farmer, and wife Ana Maria Guerra.

In 1885 he published at Porto A velhice do Padre Eterno, that generated strong criticism from Portuguese Catholic Church.

He translated into Portuguese short stories by Hans Christian Andersen.

He married Filomena Augusta da Silva Neves on 10 February 1880, the couple had two children; Maria Isabel Guerra Junqueiro on 11 November 1880, second wife without issue of Luís Augusto de Sales Pinto da Mesquita de Carvalho (1868–1931) and Júlia Guerra Junqueiro in 1881, unmarried and without issue.