David Margulis was born in 1914 in the town of Skvira, not far from Kiev. His father was a petty clerk. In 1924 his mother died, and the family moved to Kiev. David, as well as his two elder brothers Ziama and Peise, studied at a Yiddish school. In 1928, he moved to Leningrad, where his brother Peise had settled not long before. David first worked on a Jewish kolkhoz near Leningrad, then as a plumber. In 1932, he was conscripted into the Red Army and in 1933 he was sent to the Leningrad artillery school.
In 1939 and 1940, as a senior lieutenant and the commander of an artillery platoon, Margulis took part in the Finnish-Soviet ("Winter") War. It was on the Karelian Front that he was awarded the title of the Hero of the Soviet Union after his battery halted a breakthrough of Finnish soldiers on skis. Margulis was wounded during this battle.
After the German attack on the Soviet Union, as a captain in the anti-tank artillery, Margulis took part in the defense of Kiev and then of Kremenchug, in Eastern Ukraine. In 1942 and 1943 he fought in the Northern Caucasus, and later took part in the liberation of Ukraine, including Zhitomir and Berdichev, and in other operations. In the spring of 1944 Colonel Margulis was appointed commander of an artillery brigade, which should have led to his receiving the rank of general. In this capacity, he participated, inter alia, in the capture of Königsberg. He was awarded two Orders of the Patriotic War, 1st class, two Orders of the Red Banner, and other orders and medals; Margulis was wounded several times and, at least once, was sent to a military hospital in the rear.
In 1949, while studying at the Frunze Supreme Military Academy, at the peak of the Jewish Anti-Fascist Committee affair, Margulis was arrested by the MGB (which later became the KGB). He was sentenced to eight-years imprisonment (for "anti-Soviet agitation and propaganda") and sent to a camp in the Gulag. He was stripped of the title of the Hero of the Soviet Union and of all his awards. In 1955, Margulis was released and then rehabilitated. His awards, including that of the Hero of the Soviet Union were returned to him.
David Margulis died in St. Petersburg in 1993.