He succeeded founder Manuel Marulanda (alias Sureshot, in Spanish: Tirofijo) in March 2008 and commanded the Marxist rebel group until being killed in action by the Colombian Army.

His main role was originally to serve as a sort of political commissary for the urban network of the guerrilla in Bogota, and in 1978 he was appointed chief of finances for the Central High Command.

A search warrant on his apartment, where he lived with his first wife (Maria Eugenia) and son (Federico), ended in his arrest in 1981 and imprisonment in the La Modelo Penitentiary, where he founded a library.

He soon moved to the mountains to join the guerrilla soldiers, but instead of active combat he was sent to Casa Verde, the headquarters of the FARC commanders, in La Uribe (Meta), where he was recognized as an intellectual and as such was part of a number of peace dialogues with the government.

In July 2008, the Colombian Army rescued fifteen of FARC's highest-profile hostages, including Íngrid Betancourt, in Operation Jaque, further weakening the rebels' position.

On 6 March 2008, the Miami Herald stated that the national daily El Tiempo had reported troops were pursuing Cano, and he was believed to have been wounded in a 21 February helicopter attack.

President Juan Manuel Santos confirmed his death on television, claiming the Colombian army dealt the FARC "the biggest blow in the history" of the guerrilla organization.