Born in today’s Ukraine, Aleksandr Tillo was educated in the Nikolaev Cadet Corps and the Pavlovsk Military School, both in St. Petersburg. He began his military career in 1890 with 99th infantry Ivangorod Regiment. In 1905 he was promoted to the rank of captain and in 1909 transferred to the Life Guards Rifle Regiment.
Tillo participated in the 1912 Olympic Games in five military and free rifle events. In 1913 he won silver at the First Russian Olympics in the 300 metres free rifle and bronze in the free pistol shooting. One year later, at the Second All-Russian Olympics, he won gold with the military rifle, 300 metres at two targets, and with the free pistol, adding bronze with the free rifle at 50 metres.
He fought in World War I in the rank of colonel in the 5th Kyiv Grenadier Regiment. From December 1916 he commanded the 124th Voronezh Infantry Regiment. Between 1906 and 1916 he was awarded the orders of St. Stanislaus, St. Anna, and St. Vladimir.
After the October Revolution Tillo stayed in the USSR. In 1937 he worked as an instructor of the OSOAVIAKhIM, a Soviet socio-political defense organization in Leningrad. In October of that year he was arrested by the NKVD. In January 1938 a commission of the NKVD and the Prosecutor’s Office of the USSR sentenced him to death, and he was shot just days later in Leningrad.