After the outbreak of the Uprising in Montenegro, Piroli was appointed by Mussolini with complete civil and military powers in Montenegro on 25 July 1941 and as governor of Montenegro in October 1941. As recipient of the Serbian order he was considered a suitable person for cooperation with Chetniks to whom he might be presented as their former ally from a previous war. In his speech held on 7 November 1942 in Kolašin, the Chetnik commander Pavle Đurišić greeted Biroli as a great friend of the Serbs and emphasized that the people of Montenegro were very lucky that Biroli came to them at a time when they were in a very difficult position. Pirzio Biroli's brother married the daughter of Ulrich von Hassell, a member of the German Resistance against German dictator Adolf Hitler.