In 1832, Bulgakov stopped his diplomatic career and was appointed to Director of Posts in Moscow. He served in this position in 1832–1856. His younger brother Konstantin Bulgakov (1782–1835) was the Director of the Saint Petersburg Post Office at that time. Because both were the top officers of the Russian Postal Service, they could freely correspond with each other. Both brothers were much respected by their staff for their effort to improve working conditions for postal workers.