Born in Borgo San Lorenzo, at the time in the Grand Duchy of Tuscany, he was the son of Francesco Pecori Giraldi, Imperial Count[citation needed] and Florentine Patrician, titles which he would later inherit, and his wife Maria Genta.

His father had an active role in the Risorgimento, fought in the battle of Curtatone in 1848, and later become the first mayor of Borgo San Lorenzo of the newly founded Kingdom of Italy, in 1861.

After the outbreak of the Italo-Turkish War, the Kingdom of Italy sent in Libya an army corps, 34,000 men under the command of the seasoned general Carlo Caneva.

During the fights for Tripoli, he led the right column in the successful Italian attack to Ain Zara, and in December 1911, was put in command of the conquered oasis' defenses.

Wrongly informed about a group of local leaders who favored the Italians were being held captive in the nearby post of Bir Tobraz, he ordered colonel Gustavo Fara a sortie.

In the spring of 1915 when Italy declared war on Austria-Hungary, he was recalled for duty and commanded first a division and later the VII Army Corps at the lower Isonzo river.