Joseph Fahys, a French immigrant born in Belfort, Alsace, in 1832, arrived in America with his mother in 1848. He began his career apprenticing under Ulysses Savoye, one of the earliest watch case manufacturers in the United States, located in West Hoboken, New Jersey. After five years of apprenticeship, Fahys purchased his employer's business and embarked on a career that would shape the American watch case industry.

In 1861, Fahys partnered with the Fortenbach Brothers, German immigrants who had settled in Carlstadt, New Jersey, in 1852. The Fortenbachs had initially thrived in the brass industry, producing items for the Federal Army during the Civil War, including belt plates and bayonets. After the war, they successfully transitioned into silver watch case manufacturing. Together, Fahys and the Fortenbach Brothers built a significant watch case factory in Carlstadt.

By 1867, Fahys expanded his operations further by establishing a factory in Brooklyn, New York, in partnership with Wheeler, Parsons & Hayes, under the name Brooklyn Watch Case Company. This expansion marked a period of rapid growth. In 1876, Fahys bought out the Fortenbach Brothers’ interests, taking sole control of the Carlstadt plant. Soon after, he relocated the machinery and operations to Sag Harbor, Long Island.

In 1882, Joseph Fahys reorganized his business as a stock company under the name Joseph Fahys & Co. The Sag Harbor facility became a state-of-the-art manufacturing plant, employing 800 workers and producing some of the finest watch cases in the country. The factory's innovative H-shaped layout spanned 1,500 square feet and marked a significant leap in industrial watch case production.

The Fortenbach family’s involvement in the watch case business eventually dwindled after selling their interests to Fahys, and their Carlstadt factory saw various uses, including a cooperative watch case factory and later a hat factory. Despite this, their early contributions alongside Fahys laid the groundwork for a thriving industry.