He was the New York City Police Commissioner from 1926 to 1927 and president of the Brooklyn Trust Company in 1940; and vice chairman of the Triborough Bridge and Tunnel Authority.

Time magazine wrote on August 23, 1926: Last week Detective John Singer of Manhattan arrested a buck Negro for stealing a car, bought him some sandwiches and coffee, took him to Police Headquarters.

Suddenly Negro Pierce snatched a revolver from Officer Singer's hip pocket, shot him three times to the death, escaped.

John Singer was the sixth police-man to be killed on duty since January 1, 1926; eleven others had been shot, merely wounded.

George, as president of the Brooklyn Trust Company brought Walter O'Malley into the financial arrangements for Ebbets Field in 1940.