Soares was the son of João Lopes Soares (Leiria, Arrabal, 17 November 1879 – Lisbon, Campo Grande, 31 July 1970), founder of the Colégio Moderno in Lisbon, government minister and then anti-fascist republican activist who had been a priest for some time before marrying Elisa Nobre Baptista (Santarém, Pernes, 8 September 1887 – Lisbon, Campo Grande, 28 February 1955), Mário Soares's mother, at the 7th Conservatory of the Civil Register of Lisbon on 5 September 1934.
Soares adalah putra dari João Lopes Soares (Leiria, Arrabal, 17 November 1878 – Lisbon, Campo Grande, 31 Juli 1970), Pendiri Colégio Moderno di Lisbon, Menteri dan kemudian aktivis republikan anti-fasis republican yang menjadi Pendeta selama beberapa waktu sebelum menikahi Elisa Nobre Baptista (Santarém, Pernes, 8 September 1887 – Lisbon, Campo Grande, 28 Februari 1955), ibu Mário Soares, pada 5 September 1934.WikiMatrix WikiMatrix