Brunswick was a Jewish immigrant from Bremgarten, Switzerland. He came to the United States in 1834 and initially worked as an errand boy for a German butcher in New York City. In 1845 he founded the J.M. Brunswick Manufacturing Company in Cincinnati.
Originally Brunswick intended his company to be in the business of making carriages, but soon after opening his machine shop he became fascinated with billiards and decided that making billiard tables would be more lucrative.