Castellanos was born in 1883 in the , as the son of a Mexican father, Manuel Herculano de Castellanos Marín (1856–?) and of Manuela Carlota Ignacia de Jacquet, a native of Madrid and the daughter of Carlos Hipólito Jacquet Saint-Mars, a wealthy banker of French origin, who established himself as a merchant in Bilbao in 1860 and who became the city's consul of France. He had an older brother
Carlos (1881–1903), who became the first president of
Bilbao FC, while one of his cousins,
María Mestayer de Echagüe (1877–1949), known as "Maritxu", became the first gastronomic journalist in the
Basque Country and probably in Spain. According with Manuel, his father, through a friend of his from a London Credit Bank, received some football boots that were then recreated by a local shoemaker named Germán Gómez: The first "Made in Spain" boots. ==Football career==