In 1952, Fulgencio Batista led a coup against Cuba's democratic government, weeks before an election which the Partido Ortodoxo were touted to win.

In October 1958, Borrego joined a column of the 26th of July Movement's rebel army in the Escambray Mountains, which was under the command of Che Guevara.

Che decided to bring Borrego to INRA as his deputy, Aleida March as his personal assistant and José Manresa as his secretary.

Although equipped with little evidence, Cuban-American writer Servando Gonzalez, a well-known critic of Cuba, has claimed that Borrego was fired by Fidel Castro in a fit of rage for expressing his doubts over the possibility that the 1970 sugar quota would be attained.

From 1973 until 1980, Borrego served as an advisor to the Council of Ministers of Cuba, while at the same time achieving another doctorate from the Central Economic Mathematical Institute in the Soviet Union.

In 1997, alongside Che's son Ernesto, Borrego visited Lebanon, where he met with President Elias Hrawi, toured areas near the border with Israel and expressed support for the Lebanese people's struggle against Israeli occupation.

He also visited Great Britain in 2008 on a tour organised by Rock Around the Blockade where he spoke alongside philosopher Jesús Garcia and student leader Yoselin Rufin.