The psychiatrist was born in Lamego in 1901 and died in Lisbon in 1985. After finishing high school at sixteen he entered the Faculty of Medicine of the University of Lisbon where he completed his Doctorate in 1926. As a student he was taught by Professor Sobral Cid who later invited Ilharco to work with him, and later to observe his private practice.
He began working at the Bombard Psyciatric Hospital as an assistant and in 1925 was nominated as an assistant at the Psychiatric Clinic of the Faculty of Medicine, where he worked until June 1942, when he was appointed Director of Services at Júlio de Matos Hospital, which had then only been recently inaugurated.
In 1945 he was appointed Director of the Psychiatric Assistance Centre and the Central Dispensary for the Southern Zone, where he established his strategies for psychiatric assistance and mental health, particularly for the less fortunate, creating various agencies to decentralise psychiatric services. He was also a founding member of the Portuguese Society for Mental Hygiene and in 1958 he was appointed Director of the Psychiatric Assistance Institute, where he served until his retirement in 1971.