In the early 20th century, the School of St. Sava in Belgrade was renowned throughout the Orthodox world as a holy place of extreme asceticism as well as of a high quality of scholarship.

During the early part of World War I, in autumn of 1914, Popović served as a student nurse primarily in Shkodër, Niš and throughout Kosovo.

He learned of the great Russian ascetics: St. Anthony and Theodosius of the Caves in Kiev, St. Seraphim of Sarov, St. Sergius of Radonezh, St. John of Kronstadt and others.

After his year's study and sojourn in Russia, Popović entered the Theological School in Oxford, England, at the prompting of his spiritual father, Nikolaj.

Popović studied theology in London from 1916 to 1926, but his doctoral thesis under the title "Filozofija i religija F. M. Dostojevskog" (The Philosophy and Religion of Fyodor Mikhailovich Dostoevsky) was not accepted because of its radical criticism of Western humanism, rationalism, Roman Catholicism and anthropocentrism.

From 1930 to 1932, after a short period as Professor in the Theological Academy of St. Cyril and Methodius in Prizren, Serbia, he was an associate of Bishop Joseph (Cvijovich) of Bitola and the man tasked with reorganising the Church of the Carpatho-Russians in Czechoslovakia.

The area had seen an increase in those espousing Uniatism, with previously converted Christians of those regions started their conversion back into the Eastern Orthodoxy.

[citation needed] After World War II, Popović was considered ineligible by the communist government to continue as a professor at the seminary.

While Bishop Nikolaj Velimirović never returned to Yugoslavia after the World War II, Popović actively participated in the organization of the Serbian Orthodox Church.