Born in Bucharest, his parents were Petre Rosetti Bălănescu, a lawyer and landowner, and his wife Zoe ("née" Cornescu), whose father wrote the 1874 "Manualul vânătorului", prefaced with "Pseudo-cynegeticos" by Alexandru Odobescu. He attended primary school in Câmpulung, followed by his native city's Gheorghe Lazăr High School, from which he graduated in 1914. Between 1916 and 1920, he studied at the literature faculty of the University of Bucharest. His time there was interrupted by World War I: sent to the front, he was wounded in 1917 during the Battle of Mărășești. His professors included Ovid Densusianu, Ioan Bianu, , and Dimitrie Onciul. His first published work appeared in 1920 upon graduation; titled "Colindele religioase la români", the study was published in "Analele Academiei Române. Memoriile secțiunii literare". On scholarship in Paris from 1920 to 1928, he first attended the École pratique des Hautes Études, completing the program with a 1924 thesis on rhotacism in Romanian. He went on to the Sorbonne, submitting two theses in 1926: one on 16th-century Romanian phonetics, and another on Romanian letters from the late 16th and early 17th centuries in the Bistrița archives.