Pre-war

Enlisting in the Red Army in 1932, he graduated from the Mikhail Kalinin Belarusian Association Military School in Minsk in 1934, aiming to serve as a training platoon commander in the 27th Omsk Red Banner Rifle Division (Vitebsk).

In 1935 he graduated from training courses in Leningrad, before serving in the Belorussian Military District as a platoon commander, company commander, battalion chief of staff and training battalion commander of various armoured units. Commanding a tank company in the Red Army's September 1939 Polish campaign as part of the troops on the Belorussian front, he also served in the 1939–40 Winter War.

World War II

Yakubovsky entered the war in its early days on the western border as commander of a tank battalion, fighting heroically in the most difficult defensive battles in Belarus. His unit was one of the last defenders of a doomed Minsk, crushing an advanced enemy motorcycle convoy with their tanks in the city streets. From January 1942 he commanded a tank regiment of the 121st Tank Brigade on the USSR's western front, becoming Deputy Commander of the 121st Tank Brigade^[3] (January 1942) then Commander (March 1942) of the 91st Tank Brigade and participating in the Barvinkivske-Lozova offensive. He distinguished himself in the defensive battles in the Donets Basin in the summer of 1942 and in the defensive and offensive phases of the Battle of Stalingrad, fighting on the Southern, Southwestern, Stalingrad and Don fronts and rising to colonel on 30 November 1942.

In spring 1943 the brigade was transferred to the Central Front, joining the 3rd Guards Tank Army, in which he fought right up until VE Day. Commanding the brigade, he fought heroically on the Voronezh, Bryansk, Central, 1st Ukrainian fronts, in the battle of Kursk in the Orel region, in the Battle of the Dnieper and in the liberation of Kiev and Fastiv. For his heroism at Fastiv, where his unit destroyed 30 enemy tanks in a single day, Yakubovsky was awarded the title Hero of the Soviet Union.^[4] In spring 1944, at the head of his tank brigade, Col Yakubovsky successfully operated in Proskurovo-Chernivtsi offensive.

In June 1944 he became deputy commander of 6th Guards Tank Corps within 3rd Guards Tank Army. He participated in the Lvov–Sandomierz Offensive, in the battles defending and expanding the Sandomierz bridgehead, in the Vistula–Oder Offensive in January 1945. In these operations, he commanded the advanced corps troops, at their point of impact with the German tank units. For heroic actions in the Lvov-Sandomierz operation Colonel Yakubovsky was again ranked as a Hero of the Soviet Union, by decree of 23 September 1944. From April 1945 he was deputy commander of the 7th Guards Tank Corps within 3rd Guards Tank Army, participating in the Berlin and Prague operations and rising to Major-General of Tank Troops (20 April 1945).

Cold War

After the war, he continued to serve as deputy commander of the tank corps in the Leningrad Military District. In 1948 he graduated from the General Staff Academy. In March 1948 he became Commander of the Armored Division in the Belorussian Military District then in April 1952 became commander of armoured and mechanized forces in the Carpathian Military District. Rising to Lieutenant-General of Tank Forces (3.05.1953), he commanded a Tank Army (December 1953 to April 1957) then a mechanized army (from April 1957).

In July 1957 he became First Deputy Commander of the Group of Soviet Forces in Germany, later being promoted to Colonel-General (18.08.1958). In April 1960 he was appointed Commander of the Group of Soviet Forces in Germany, being in post in the midst of the Berlin Crisis of 1961, when the threat of armed conflict in Europe dramatically escalated. During the crisis, in August 1961, Ivan Konev, Commander in Chief of the Group of Soviet Forces in Germany, was appointed Marshal of the Soviet Union and Yakubovsky was transferred to the post of his first deputy, while continuing to manage the daily operations of the Group of Soviet Forces in Germany. After stabilizing the situation in April 1962, Army General Yakubovsky again returned to the post of Commander of the Group of Soviet Forces in Germany. In January 1965 he was made Commander of the Kiev Military District.

On 12 April 1967 he was made First Deputy Minister of Defense of the USSR (simultaneously with the appointment of Andrei Grechko as Minister of Defense) and Marshal of the Soviet Union, whilst from July that year he contiguously held the post of supreme commander of the forces of the Warsaw Pact.^{[citation needed]} In this capacity, he directed military preparations for the Warsaw Pact invasion of Czechoslovakia in August 1968.^{[citation needed]}