In August 1905, Leon Hirsch, an established importer of Swiss movements, leased a portion of the factory that had formerly been occupied by the Courvoisier Wilcox Mfg. Company in Newark, New Jersey. His plan was to expand his existing business by manufacturing gold watch cases at the Newark plant.

The Leon Watch Case Company was officially incorporated in January 1906 by Leon Hirsch and Ferdinand Hirsch. The earliest advertisements for the company included the sales location at 37 Maiden Lane in New York City, a location used by Leon Hirsch for his retail operation since April 1899.

The company specialized in manufacturing 14K solid gold watch cases and advertised that their bows were even marked "14K." Advertisements appearing in late 1905 indicated that the case factory was located at 22-26 Boyden Place in Newark, New Jersey, while the New York office was at 37-39 Maiden Lane. According to promotions, every watch case produced by the company was stamped "Leon Warranted -14 K-." In August 1905, The Jewelers' Circular Weekly also published a small list of trademarks, indicating the company also utilized "Leon W. C. Co."

When the company was incorporated in January 1906, the factory location given by The Jewelers' Circular Weekly was "16 Boyden St." in Newark.

In February 1906, Leon Hirsch formed a corporation under his name to continue the importing business from the sales office on Maiden Lane. This company was established separately from the case company.

By August 1906, the Leon Watch Case Company had opened an additional sales office in Chicago at 52 State Street. Advertisements from this era provide the New York Office address at 37-39 Maiden Lane and the factory address at 16 Boyden Place in Newark, New Jersey.

Through the fall of 1908, the company frequently advertised in The Jewelers' Circular Weekly. After the advertising campaigns ceased, the last mention of the Leon Watch Case Company in this trade publication was in the April 5, 1910 issue, reporting a traveling salesman from the company was visiting Cleveland.

The retail operation owned by Leon Hirsch was still being advertised at the 37 Maiden Lane location as late as the 1920s. It is unknown when the case production at the Newark factory was terminated, but a classified ad published in the April 24, 1915 issue of the Newark Evening Star advertised eight "fine watch case lathes" and "engine turners' lathes" for sale.