He entered Leningrad Theological Seminary in 1947, and graduated in 1949. He then entered the Leningrad Theological Academy (now Saint Petersburg Theological Seminary), and graduated in 1953. On April 15, 1950, he was ordained a deacon by Metropolitan Gregory (Chukov) of Leningrad, and on April 17, 1950, he was ordained a priest and appointed rector of the Theophany church in city of Johvi, Estonia, in the Tallinn Diocese. On July 15, 1957, Fr. Alexei was appointed Rector of the Cathedral of the Dormition in Tallinn and Dean of the Tartu district. He was elevation to the rank of Archpriest on August 17, 1958, and on March 30, 1959, he was appointed Dean of the united Tartu-Viljandi deanery of the Tallinn diocese. On March 3, 1961, he was tonsured a monk in the Trinity Cathedral of Holy Tri