Mario Berti was born in La Spezia, which is located in modern-day Liguria. He was born into an upper-middle-class family. His family was quite wealthy, partly because his father was granted land in La Spezia after the Mille Expedition of Garibaldi. Berti never married and never had children, but he had two nephews and a niece, who were his only heirs.
World War I
He achieved the rank of colonel at an extremely young age. Originally stationed in Libya by the outbreak of the war, he served on the Trento front in 1916. He saw action at the Battle of Asiago. Berti earned the British Distinguished Service Order and was personally decorated by Winston Churchill for his services to the Allies in World War I. He would later be awarded by Hitler with the Iron Cross.
At the beginning of the war Berti was Chief of Staff in the Italian Army. However Italy's commitment in Spain had drained it of resources which made it not ready to fight against Britain and France. Many Generals including Berti made this clear to Mussolini. As a result, he was demoted and sidelined. He was appointed Commissioner of Libya. He had fallen out of favour with Mussolini and Graziani had taken his place. His relation with Graziani was abysmal. After the failures in Egypt, Berti called Graziani incompetent and refused to send him help. During his sick leave with fever, Graziani called him a coward and had him dishonored. In the summer of 1940, Berti replaced Francesco Guidi as the commander of the Italian Tenth Army in Libya. On 13 September 1940, Berti was in command of the Tenth Army during the Italian invasion of Egypt. Halted at Sidi Barrani by logistical problems, Berti deployed his advanced units in a series of fortified strongpoints. He then began work on extending the Via Balbia into Egypt. The fortified strongpoints were not mutually supporting. Large gaps between them were only covered by motorised patrols. A build-up for a new Italian offensive further into Egypt was delayed by the Italian invasion of Greece. The offensive in Egypt was rescheduled and a mid-December launch was planned. However, prior to this, General Berti went on sick leave and Italo Gariboldi took his place temporarily. On 9 December 1940, Berti was on leave when British General Richard O'Connor launched Operation Compass. On 14 December, Berti arrived back in North Africa. The British forces had exploited the gaps between the Italian fortified camps and in three days were able to overrun them and to capture or destroy almost all of the Italian defenders. On 11 December, Sidi Barrani fell. By 16 December, the Italians had been ejected from Egypt. On 23 December, Berti was replaced by General Giuseppe Tellera as commander of the Tenth Army. Tellera was to die in action at Beda Fomm. On September 8, 1943, Italy signed an armistice with the allies. At that point he retired from the Army. After the war he was cleared of wrongdoing. The post-war government arrested Graziani and asked Berti if he was a criminal. Berti made it clear that Graziani had done no wrong. He lived in the hills of La Spezia for the rest of his life. He is not to be confused with Col. Berti, who was known as a "sly murderer".