Born in Havana, he became involved in Cuba's turbulent left-wing politics as a young man, joining the tiny Popular Socialist Party, the Moscow-line predecessor of the Communist Party, during the years of right-wing regimes that preceded the 1959 revolution.
The PSP at first played little part in Fidel Castro's armed struggle against the dictatorship of General Fulgencio Batista, which took place mainly in the countryside, and only threw its weight behind Castro's guerrilla campaign a few months before Batista finally fled the country.
Despite this background of mistrust, when Castro moved the revolution sharply to the left in the early 1960s, he found a use for the PSP apparatus, and for young but experienced activists such as Malmierca, in giving a disciplined organizational underpinning to his embryonic regime.
He was also one of the functionaries who supervised the merger of the PSP with Castro's July 26 Movement to form the Cuban Communist Party in 1965.
He performed this difficult task well enough to earn advancement, becoming a member of the new party's central committee and being made editor of its official organ, the daily newspaper Granma.