Banker was born at Passaic, New Jersey, on 25 October 1892. After graduating from Barnard College she joined American Telephone and Telegraph Company (AT&T) where she worked as a switchboards instructor. During World War I Banker was chosen to head a team of thirty-three telephone operators of Telephone Unit No. 1, for telephone operations, assigned to war duty in France. This was the first group of women who were given the popular name Hello Girls.
