Pinochet was born in Valparaíso on November 25, 1915, the son of Augusto Pinochet Vera (descendant of Bretonimmigrants who arrived in Chile during the 18th century) and Avelina Ugarte Martínez. He went to primary and secondary school at the San Rafael Seminary of Valparaíso, the Rafael Ariztía Institute (Marist Brothers) in Quillota, the French Fathers' School of Valparaíso, and in the Military School, which he entered in 1933. After four years of study, in 1937 he graduated with the rank of alférez (Second Lieutenant) in the infantry.
In September 1937, he was assigned to the "Chacabuco" Regiment, in Concepción. Two years later, in 1939, then with the rank of sub-lieutenant, he moved to the "Maipo" Regiment, garrisoned in Valparaíso. He returned to Infantry School in 1940. On January 30, 1943, he married Lucía Hiriart Rodríguez, with whom he had five children: three daughters (Inés Lucía, María Verónica, Jacqueline Marie) and two sons (Augusto Osvaldo and Marco Antonio).
At the end of 1945, he was assigned to the "Carampangue" Regiment in the northern city of Iquique. In 1948, he entered the War Academy, but he had to postpone his studies, because, being the youngest officer, he had to carry out a service mission in the coal zone of Lota. The following year, he returned to his studies in the Academy.
After obtaining the title of Officer Chief of Staff, in 1951, he returned to teach at the Military School. At the same time, he worked as a teachers' aide at the War Academy, giving military geography and geopolitics classes. In addition to this, he was active as editor of the institutional magazine Cien Águilas ("One Hundred Eagles").
At the beginning of 1953, with the rank of major, he was sent for two years to the "Rancagua" Regiment in Arica. While there, he was appointed professor of the War Academy, and he returned to Santiago to take up his new position. He also obtained a baccalaureate, and with this degree, he entered the University of Chile's Law School.
In 1956, Pinochet was chosen, together with a group of other young officers, to form a military mission that would collaborate in the organization of the War Academy of Ecuador in Quito, which forced him to suspend his law studies. He remained with the Quito mission for three-and-a-half years, during which time he dedicated himself to the study of geopolitics, military geography and intelligence.
At the end of 1959, he returned to Chile and was sent to General Headquarters of the I Army Division, based in Antofagasta. The following year, he was appointed Commander of the "Esmeralda" Regiment. Due to his success in this position, he was appointed Sub-director of the War Academy in 1963.
In 1968, he was named Chief of Staff of the II Army Division, based in Santiago, and at the end of that year, he was promoted to Brigadier General and Commander in Chief of the VI Division, garrisoned in Iquique. In his new function, he was also appointed Intendant of the Tarapacá Province.
In January 1971, he rose to Division General, and was named General Commander of the Santiago Army Garrison. At the beginning of 1972, he was appointed General Chief of Staff of the Army. With rising domestic strife in Chile, Pinochet was appointed Army Commander in Chief on August 23, 1973 by President Salvador Allende, his masonic brother of the same lodge, just the day after Parliament voted a resolution calling Allende's removal, by force if necessary.