He was born in Bucharest in 1890. After graduating from military school with the rank of second lieutenant, he participated in the Second Balkan War in 1913, and then promoted to lieutenant. At the start of World War I he fought at the Battle of Turtucaia in 1916, after which he was promoted to captain and then to major the next year. After the war, Alinescu pursued his studies at the Higher War School (1919–1921), after which he was promoted to lieutenant colonel in 1927, to colonel in 1934, and to brigadier general in 1939.