Career
When the order was suppressed, he continued his studies and was ordained. In 1781, he moved to the United States and worked with the Diocese of Baltimore. In May 1793 Graessel was named coadjutor of the diocese by the priests but died of yellow fever in October 1793.
On December 8, 1793, Pope Pius VI confirmed Graessel coadjutor bishop and titular bishop of "Samosata," not knowing Graessel had died.