From 1913 to 1915, Solacolu completed two years of studies at the University of Bucharest's law faculty. During those years, with Romania still neutral in what became World War I, Solacolu was marginally involved with the literary-political circles of Alexandru Bogdan-Pitești and Ioan Slavici, which were supportive of the Central Powers. Decades later, he confessed to having purposefully stayed away from controversy, only publishing neutral literature in Slavici's "Ziua"; he also recalled seeing a passive Slavici taking orders from Bogdan-Pitești, the alleged spy. Solacolu was drafted into the Land Forces, upon Romania's entry into war. Part of his family remained in Bucharest, which soon fell to the Germans. Barbu followed the army on its northeastern retreat, went to the Iași military school, and eventually participated in the Budapest Campaign as a second lieutenant in the cavalry. He received the Military Virtue Medal and was an Officer of the Order of the Crown.