In August 1916, at the start of the Romanian Campaign of World War I, Rosetti was a major in the Romanian Army, serving as chief of the operations bureau for the general staff at the General Military Headquarters in Periș. In this position, he objected to the numerous promotions made two days before the fall of Bucharest to the Central Powers, ostensibly to raise officer morale. He believed promotions for their own sake cheapened the meaning of rank and eroded respect for the hierarchy. Although he too was promoted to lieutenant colonel on 22 November, he noted in his diary that he was not at all pleased with the honor.