Patriarch Miron Cristea selected him alone, of all 1930 seminary graduates, to receive a scholarship and take his licentiate in theology at the University of Athens.

Cristea, following Moisescu's progress, sent him (upon the recommendation of the University of Athens and of the Romanian Embassy in Greece) to continue his advanced studies at the Faculty of Roman Catholic Theology at the Université des Sciences Humaines in Strasbourg.

These courses were examined by professors Milan Șesan and Vladimir Prelipceanu, who “determined their scientific and didactic value, as well as their full harmony with the teachings of the Orthodox Church”.

Another series of promotions followed after a turn unforeseen by many at the time, but in the best tradition of precedents not only Byzantine, but also Eastern European and even Romanian, especially Transylvanian: witness Photius’ elevation to Patriarch of Constantinople from general, Ambrose becoming Bishop of Milan from civil administrator, professor Nicolae Bălan becoming Metropolitan of Transylvania, etc.

On February 23, 1956, Vicar Bishop Teoctist Arăpașu ordained him deacon; the next day, the other Patriarchal Vicar Bishop, Antim Nica, ordained him priest, and on February 26, the National Church Council, gathered in electoral college according to its statute’s provisions, elected him Archbishop of Sibiu and Metropolitan of Transylvania.

Before Moisescu’s election as Metropolitan of Transylvania, Patriarch Justinian, in a long, meaningful and well-considered speech before the electoral college, described thus the candidate who should be elected: “There we will have to send the best of today’s clerics from our Church, a vigorously well-rounded personality, with a distinguished theological preparation, thoroughly aware of all the problems that our contemporary world presents”, for “new times require new people”.

On January 10, 1957, he was elected Metropolitan of Moldavia and Suceava, and three days later he was installed in the seat once held by Dosoftei, Varlaam, Veniamin Costache, to name only the most prominent of his predecessors at Iași.

Upon his election as Metropolitan of Moldavia and Suceava, he described his programme thus: “With all my efforts I will undertake with steadfast resolve to protect and keep the Holy places: churches, monasteries and sketes – glorious works of art – that form the diadem of the Metropolitanate of Moldavia; and for those who need these treasures of our ancient faith, I will strive to produce priests who are hard-working and devoted to the Church, the Fatherland and the good of the people.

New buildings – veritable architectural monuments – were erected on the grounds of the Iași diocesan centre, while his Cathedral and residence were redone.

He restored, in full or in part, over twenty monasteries and sketes: Putna, Sucevița, Moldovița, Voroneț, Arbore, Humor, Slatina, Dobrovăț, Cetățuia, Râșca, Neamț, Sihăstria, Secu, Bistrița, Văratec.

As metropolitan, he published numerous articles, pastoral letters, speeches and editorials, especially in the magazine Mitropolia Moldovei și Sucevei, which appeared for twenty years under his direct supervision.

In addition, the Iaşi Metropolitan Centre edited other works, among them Monumente istorice-bisericești din Mitropolia Moldovei și Sucevei (1974) and Psaltirea în versuri a lui Dosoftei, ediție critică (1975); the monographs Catedrala Mitropolitană din Iașui and Mănăstirea Cetățuia (both 1977); brochure-albums to popularise the monasteries of Moldavia, prayer books, etc.

He began the great collection Părinți și scriitori bisericești (projected to span 90 volumes), as well as the six-volume set Arta creștină în România.