Thomas Seitz was born in Oberweier, Karlsruhe, Germany.    He and his brothers Michael and Joseph emigrated to America in 1853 and settled on the west bank of the Mississippi River in Ste. Genevieve County, Missouri.    Joseph died almost immediatly upon arriving to the area, on August 31, 1853.  Thomas married Mary Anne Grieshaber on November 30th of the next year.  They had nine children together. 

In around this time Thomas and Michael started a brewery in the town of New Offenburg.  Among their employees was a man named Valentine Rottler.  The Seitz Brothers ran the brewery for about a decade before admitting Rottler as a partner, and finally selling the firm to him outright in around 1859.  

The brothers removed to Middle Brook and set up another brewery on the banks of Middlebrook Creek.  Thomas ran that brewery until his death on the 13th of June, 1876 at the age of 48 years.

Michael by this time had become a farmer, but Thomas's sons Edward and Henry continued operating the brewery through 1880.  Later that year Edward, the oldest, also died at the age of 21 and thereafter the  brewery ceased to be.