Militão founded the Photographia Americana studio in 1875, where his clients included Castro Alves, Joaquim Nabuco, Dom Pedro II, and Empress Teresa Cristina.

The location of the studio in front of the Church of Our Lady of the Rosary, frequented mainly by the Afro-Brazilian residents, led to his photography of prominent Black citizens of Brazil.

[1][2][3][4] A collection of more than 12,000 photos produced by Militão de Azevedo was acquired by the Roberto Marinho Foundation in 1996 and donated to the Museu do Ipiranga of the University of São Paulo.

[5] Militão worked mainly in São Paulo between 1862 and 1887, producing images of houses, farms, public buildings, streets and panoramic shots; and organized albums with some of these urban scenes.

[1] Some of his famous clients were the emperor, Dom Pedro II, the Empress Teresa Cristina, the jurist and politician Ruy Barbosa, the poet Castro Alves, the abolitionists Luís Gama and Joaquim Nabuco, Antônio de Lacerda Franco, José Maria Lisbon, Eduardo da Silva Prado, Friar Germano de Annecy and Rodolfo Amoedo.

Despite disposing of the entire Photographia Americana laboratory and auctioning off photographic machines, materials and equipment, Militão kept the textual and iconographic documentation of the business.

Militão Augusto de Azevedo Collection at the Paulista Museum of the University of São Paulo is made up of the documentation and office ephemera from Carneiro & Gaspar and Photographia Americana.