He and his sister Haydée Santamaría participated in the failed attack on the Moncada Barracks led by Fidel Castro, during which he was captured and subsequently killed in prison.

He and his sister Haydée allowed revolutionaries including Fidel Castro to use their tiny two-room apartment on the corner of O and 25th streets in Havana for planning the revolution.

Abel and Haydee participated in the Moncada barracks assault in July 1953 that was intended to start the revolutionary overthrow of Cuban dictator Fulgencio Batista.

Fidel Castro assigned Santamaria with the mission of taking the Saturnino Lora Hospital as part of the assault.

Abel was murdered in prison in Santiago de Cuba after being tortured by police to reveal the location where the other revolutionaries were hiding.