Born in Talca in 1925, Gacitúa began his musical training when he was five.[3] At eight, he made his debut with the violinist Pedro Dandurain[3] and then, when he was 12, he performed in Santiago with the Symphony Orchestra.[3] It was at Arrau's arguing that the piano stopped being a hobby for him.
In the 1950s, Gacitúa received very a positive review in the US, which has support when The New York Times stated "Chile, that has already produced with Claudio Arrau a pianist of first magnitude, it seems to have another with Gacitúa."[3] Similarly, he received offers to start an international career as a soloist. However, he chose to return to the country because he "preferred to settle in Chile and be a mouse head" as he said in an interview in 1990.
On 5 December 2001, Gacitúa committed suicide at the Alcántara metro station of the Santiago Metro; he was 76 years old.[4][5] According his daughter Rebeca, he suffered depression[3] and his other son Óscar couldn't stop Gacitúa Weston's desire to die, so his decision was premeditated.[3] One of the reasons of his depression was his old age,[3] because he believed entering Alzheimer's disease despite having entirely organized a successful piano seasons or teach private piano lessons at his home in Providencia.[3]