A leading member of the Socialist Party, served as Minister of Foreign Affairs of Chile from 1970 to 1973 during the Presidency of Salvador Allende.

With the victory of Salvador Allende in the 1970 Chilean presidential elections, Almeyda was appointed to the post of the Ministry of Foreign Affairs.

This was when he made a "castling" with Orlando Letelier (then Minister of the Interior), in order to avoid being the object of censorship by National Congress by means of a motion of no confidence.

Such conviction mainly meant the loss of the exercise of their citizenship rights and he could only be rehabilitated as a citizen once the country had returned to democratic normality, by the same court that sentenced it.

During the government of Patricio Aylwin he was in charge of reopening the Chilean embassy in the Soviet Union during the last months of the Eastern Bloc.