With his wife Nina Borovko-Langlet in Budapest, he is credited with saving many Jews from the Holocaust, by providing Swedish documents saying that people were waiting for Swedish nationality.
Raoul Wallenberg was inspired by Langlet and used the same method to save Jewish people when he came to Budapest.
In 1965, Valdemar and Nina Langlet were recognized as Righteous Among the Nations by Yad Vashem.