Born in Lamego, Portugal in 1930, Lemos Pires moved to Lisbon at age 18 to commence his studies at the Portuguese Military Academy.

By the late 1960s, he was posted back to Portugal, where he administered physical education programs for the army, but was soon sent to Portuguese Guinea, under the command of Military Governor António de Spínola, raising to the rank of colonel.

In August 1975, one of those political parties, the Timorese Democratic Union (UDT), staged a coup against the Portuguese administration, prompting the outbreak of a three-month civil war, with many UDT politicians and supporters fleeing across the border to West Timor in Indonesia, where they were required to sign a petition calling for East Timor's incorporation into Indonesia.

Without any possibility of support from Portugal, Lemos Pires maintained his administration for three months until he ordered a withdrawal of staff and left his post for Lisbon on 27 November 1975.

"[1] On his return to Lisbon, Pires was appointed commander of the Training Center for Special Operations and lectured at the Institute for Advanced Military Studies, of which he was deputy director.