Joaquin Maurin was born in Bonansa, Spain in 1896. Maurin developed an interest in politics while teaching history during the First World War. He joined the Juventud Republicana and contributed to its daily newspaper, El Ideal.

In 1920 Maurin joined the National Confederation of Trabajo (CNT), the anarcho-syndicalist trade union and was appointed editor of its journal La Lucha Social. Maurin became a Marxist and in 1921 he travelled to Russia where he attended the Third Congress of the Comintern. On his return to Spain he founded the Marxist trade-union weekly, La Batalla.

Maurin was imprisoned for the first time for his political activities in 1923. He served a total of three years in prison before being forced into exile in 1930.

After Miguel Primo de Rivera lost power Maurin returned to Spain and once again began publishing La Batallaand a Marxist theoretical journal, La Nueva Era. In 1931 he established the Workers' and Peasants' Party (BOC). He became secretary general of BOC but its membership never exceeded a few thousand.

In September 1935 Maurin joined with Andres Nin to form the Workers Party of Marxist Unification (POUM). This revolutionary anti-Stalinist Communist party was strongly influenced by the political ideas of Leon Trotsky. The group supported the collectivization of the means of production and agreed with Trotsky's concept of permanent revolution.

As a result of Maurin's involvement, POUM was very strong in Catalonia. In most areas of Spain it made little impact and in 1935 POUM is estimated to have only around 8,000 members. In the elections of February 1936, Maurin was the only party member to win a seat in the Cortes.

Maurin was at a POUM meeting in Galicia when the military uprising took place on 18th July 1936. In territory controlled by the Nationalist Army Maurin went into hiding. Although carrying false papers he was arrested while trying to get into the Republican zone in September 1937.

Unlike many leaders of the Republican movement, Maurin's life was spared due to the intervention of a high-ranking relative in Franco's military. After spending nine years in prison Maurin was released in October 1946.

Maurin emigrated to the United States and settled in New York where he established the American Literary Agency (ALA), an organization that promoted the works of Latin American writers. Joaquin Maurin died in 1973.