Considered one of the greatest Spanish-language poets of the 20th century, Neruda was a prolific writer, his output ranging from erotically charged love poems, surrealist poems, historical epics, and overtly political poems, to poems on common things, like nature and the sea. Colombian novelist Gabriel García Márquez has called him "the greatest poet of the 20th century in any language".

In 1927, Neruda began his long career as a diplomat in the Latin American tradition of honoring poets with diplomatic assignments. After serving as honorary consul in Burma, Neruda was named Chilean consul in Buenos Aires, Argentina, in 1933. While there, he began a friendship with the visiting Spanish poet Federico García Lorca. After transferring to Madrid later that year, Neruda also met Spanish writer Manuel Altolaguirre. Together the two men founded a literary review called Caballo verde para la poesîa in 1935. The outbreak of the Spanish Civil War in 1936 interrupted Neruda's poetic and political development. He chronicled the horrendous years which included the execution of García Lorca in Espana en el corazon (1937), published from the war front. Neruda's outspoken sympathy for the loyalist cause during the Spanish Civil War led to his recall from Madrid in 1937. He then returned to Europe to help settle republican refugees in the United States.

Neruda returned to Chile in 1938 where he renewed his political activity and wrote prolifically. Named Chilean Consul to Mexico in 1939, Neruda left Chile again for four years. Upon returning to Chile in 1943, he was elected to the Senate and joined the Communist Party. When the Chilean government moved to the right, they declared communism illegal and expelled Neruda from the Senate. He went into hiding. During those years he wrote and published Canto general (1950).

In 1952 the government withdrew the order to arrest leftist writers and political figures, and Neruda returned to Chile and married Matilde Urrutia, his third wife (his first two marriages, to Maria Antonieta Haagenar Vogelzang and Delia del Carril, both ended in divorce). For the next twenty-one years, he continued a career that integrated private and public concerns and became known as the people's poet. During this time, Neruda received numerous prestigious awards, including the International Peace Prize in 1950, the Lenin Peace Prize and the Stalin Peace Prize in 1953, and the Nobel Prize for Literature in 1971.