He tried many jobs and successively as postman, grocer, freight agent on the new Auburn and Syracuse Railroad. In 1842 he became a messenger for Pomeroy and Company, the express firm between Albany and Buffalo and in the next year was named their agent in Buffalo.
In 1844 he became an agent for Wells and Company, becoming one of the three owners of the firm. He managed all express operations west of Buffalo, New York.
Wells and Fargo formed American Express in 1850. During that time, many Americans had gone west in search of gold. Wells and Fargo realized that they could make a lot of money by offering banking services to these people.
In March 1852, Wells and Fargo organized a company to deliver mails, packages and paper from the East to San Francisco. From there the shipments would distribute to California mining camps.
The business became so successful that Wells Fargo also entered banking, dropping off packages at mining camps, purchasing gold dust for $15 an ounce, and later selling it to the US mint for $18.
In 1861 William Fargo was elected Mayor of Buffalo on the Democratic ticket.
William George Fargo (1818 – 1881)