Following Romanov tradition, Andrei was destined to follow a military career. While his eldest brother, Kirill, chose the Imperial navy, Andrei and his brother Boris joined the infantry. Andrei began his military service in August 1898 as lieutenant in the Guards Horse-Artillery Brigade. In 1899 he was appointed adjutant, graduating in 1902 from the Mikhailovsky Artillery School. He then studied law at the Alexandrovskaya Military Law Academy at Potseluev bridge, graduating with honors in 1905. He was subsequently listed by the military-judicial department. The military law Academy tasked him with translating foreign military criminal statutes. He was appointed lieutenant in 1902, captain in 1906 and colonel on 18 April 1910. In March 1911, he was appointed senator. From 1911 to 26 February 1914, he commanded the Life Guards 2nd Don Cossack artillery. In spite of his appointments, Grand Duke Andrei did not have much interest in his military career. Instead, he pursued a life of leisure enjoying the privileges provided by his royal status and wealth.