He became a diplomat, and beginning in 1941, he worked as the chargé d'affaires for Chile in Bucharest, Romania.

Del Campo began issuing Chilean passports to Polish Jews, saving them from deportation.

He repeatedly pleaded with the Romanian government to save those who he had issued documents to, and according to Romanian historian Anca Tudorancea, “minutes from the Romanian Council of Ministers show that Samuel del Campo became a nuisance at the highest level.”[4] Yad Vashem estimates that Del Campo rescued approximately 1,200 Jews by giving them passports, despite the Chilean government's official non-interference policy.

In the spring of 1943, as the tide of war went against the Axis, diplomatic relations between Romania and Chile were severed.

[2] He was recognized by Yad Vashem as a Righteous Among the Nations on November 23, 2016, 56 years after his death.