 Born into the princely Giedraičiai family, he inherited a much neglected diocese that was reduced to only about 20 priests.He became known for his devotion and work to end clerical abuses, strengthen churches and schools, and increase the number of priests.Giedraitis invited the Jesuits to Kražiai where the Kražiai College was established already after his death and the Bernadines to Kretinga where they established the first monastery in Samogitia.