Born in Brăila into a family of low-ranking civil servants, Andrei attended Nicolae Bălcescu High School from 1902 to 1910. He then moved to Iași, where he enrolled in the literature and philosophy faculty of Iași University, graduating in 1913. While a student, his mentor was Ion Petrovici. He continued his education in Berlin, where he audited a seminar on logic and history of philosophy, and in Leipzig. Returning home when the war broke out, he volunteered for service, in spite of being exempt due to the fact that his father was deceased. He was assigned to an infantry regiment in March 1915, and from July to September 1916, during which time Romania entered the war, he attended the reserve officers' school in Târgoviște. He was sent to another regiment, effective November, and distinguished himself in the battles at Oituz, Slănic and the Cașin valley. For his acts of bravery, he was awarded the Order of the Star of Romania, the Order of the Crown and War Cross with Bars.