While studying at the seminary, he joined the Order of Dominican Fathers.

After graduating from the seminary in 1984, Vialikaselets was ordained a priest by Cardinal Julijans Vaivods and was directed to his first parish of the Holy Trinity in Ishkaldz, Brest Region, Belarus.

In addition to the pastoral ministry of Father Vialikaselets dealt with the reconstruction and renovation of temples.

In 1992 he was appointed Vicar General of the Diocese of Pinsk, while performing duties of dean of the Baranavichy Decanate and pastor of the Church of the Holy Cross in Baranavichy.

On January 3, 2020, Vialikasieliets was appointed Apostolic Administrator of the Roman Catholic Archdiocese of Minsk–Mohilev following the resignation of Archbishop Tadevush Kandrusevich.