Vasilevsky began his military career during World War I, earning the rank of captain by 1917. At the start of the October Revolution and the Civil War he was conscripted into the Red Army, taking part in the Polish-Soviet War. After the war, he quickly rose through the ranks, becoming a regimental commander by 1930. In this position, he showed great skill in organizing and training his troops. Vasilevsky's talent was noticed, and in 1931 he was appointed a member of the Directorate of Military Training. In 1937, following Stalin's Great Purge, he was promoted to General Staff officer.
At the start of the 1943 Soviet counteroffensive of World War II, Vasilevsky coordinated and executed the Red Army's offensive on the upper Don, in the Donbass, Crimea, Belarus and Baltic states, ending the war with the capture of Königsberg in April 1945. In July 1945, he was appointed Commander-in-Chief of Soviet forces in the Far East, executing the Manchurian Strategic Offensive Operation and subsequently accepting Japan's surrender. After the war, he became the Soviet Defense Minister, a position he held until Stalin's death in 1953. With Nikita Khrushchev's rise, Vasilevsky began losing power and was eventually pensioned off. After his death, he was buried in the Kremlin Wall Necropolis in recognition of his past service and contributions to his nation.
Vasilevsky was born on September 30, 1895 in Novaya Golchikha in the Kineshma Uyezd (now part of the city of Vichuga in the Ivanovo Oblast) in a family of Russian ethnicity. Vasilevsky was the fourth of eight children. His father, Mikhail Aleksandrovich Vasilevsky, was a priest to the nearby St. Nicholas Church. His mother, Nadezhda Ivanovna Sokolova, was the daughter of a priest in the nearby village of Ugletz. Vasilevsky reportedly broke off all contact with his parents after 1926 because of his Communist Party membership and his military duties in the Red Army; three of his brothers did so also. However, the family resumed relations in 1940, following Joseph Stalin's suggestion that they do so.
According to Vasilevsky, his family was extremely poor. His father spent most of his time working to earn money, while the children assisted by working in the fields. In 1897, the family moved to Novopokrovskoe, where his father became a priest to the newly built Ascension Church, and where Aleksandr began his education in the church school. In 1909, he entered Kostroma seminary, which required considerable financial sacrifice on the part of his parents. The same year, a ministerial directive preventing former seminarists from starting university studies initiated a nationwide seminarist movement, with classes stopping in most Russian seminaries. Vasilevsky, among others, was expelled from Kostroma, and only returned several months later, after the seminarists' demands had been satisfied.
After completing his studies in the seminary and spending a few years working as a teacher, Vasilevsky intended to become an agronomist or a surveyor, but the outbreak of the First World War changed his plans. According to his own words, he was "overwhelmed with patriotic feelings" and decided to become a soldier instead. Vasilevsky took his exams in January 1915 and entered the Alexander Military Law Academy in February. As he recalls, "I did not decide to become an officer to start a military career. I still wanted to be an agronomist and work in some remote corner of Russia after the war. I could not suppose that my country would change, and I would." After four months of courses that he later considered to be completely outdated, theoretical, and inappropriate for modern warfare, he was sent to the front with the rank of praporshchik, the highest non-commissioned rank in the Russian infantry, in May 1915.
From June to September, Vasilevsky was assigned to a series of reserve regiments, and finally arrived at the front in September as a half-company commander (polurotny) in the 409th Novokhopersky regiment, 109th division, 9th Army. In the spring of 1916, Vasilevsky took command of a company, which eventually became one of the most recognized in the regiment. In May 1916, he led his men during the Brusilov offensive, becoming a battalion commander after heavy casualties among officers, and gaining the rank of captain by age 22.
In November 1917, just after the Russian Revolution, Vasilevsky decided to end his military career. As he wrote in his memoirs, "There was a time when I led soldiers to battle, thinking I was doing my duty as a Russian patriot. However, I understood that we have been cheated, that people needed peace.... Therefore, my military career had to end. With no remorse, I could go back to my favorite occupation, working in the field." He travelled from Romania, where his unit was deployed in 1917, back to his own village.