He continued to serve as Bishop of Würzburg, though without temporal power, until his death. He was also Bishop of Bamberg from 1805 until his death. Georg Karl Ignaz von Fechenbach zu Laudenbach was born in Mainz on February 20, 1749.
He was ordained as a priest on February 18, 1779.
On March 12, 1795, the cathedral chapter of Würzburg Cathedral elected him to be the new Prince-Bishop of Würzburg, with Pope Pius VI confirming his appointment on April 1, 1795. He was consecrated as a bishop by Karl Theodor Anton Maria von Dalberg on June 21, 1795.
On March 26, 1800, the cathedral chapter of Bamberg Cathedral elected him to be coadjutor bishop of the Prince-Bishopric of Bamberg. The Treaty of Lunéville of February 9, 1801 decreed the secularization of the German prince-bishoprics.
Bamberg was mediatised to the Electorate of Bavaria in 1802.
The bishop fought bitterly to maintain his control of the Prince-Bishopric of Würzburg, but on February 25, 1803, the prince-bishopric was mediatised to the Electorate of Bavaria. He remained bishop, but no longer exercised temporal power in Würzburg. On September 15, 1805, the Bishop of Bamberg, Christoph Franz von Buseck, died, and Fechenbach succeeded as Bishop of Bamberg.
He died in Bamberg on April 9, 1808.