Following the death of Franz von Mendelssohn and Paul von Mendelssohn-Bartholdy in 1935, Löb was appointed as chairman of Mendelssohn & Co. bank as the first non-family member.

In the 1930s, he served as the Belgian General Consul in Berlin.

In 1938, he was pressured by the Nazis' Aryanisation policy to break up Mendelssohn & Co. and hand over most of its assets to Deutsche Bank.

Löb emigrated to Argentina in 1939 and to the United States in 1948.

This German business-related biographical article is a stub.