Saint Joasaph was born in Priluki, Poltava province, on September 8, 1705, on the feast of the Nativity of the Most Holy Theotokos. At Baptism he was named Joachim. He came from the ancient pious Little Russian Gorlenkov family. In 1712, 7-year-old Joachim was sent by his father to the Kiev Theological Academy. Within the walls of the academy, he felt attracted to the monastic life. For 7 years, the future saint tested himself and finally opened up to his parents. For a long time, mother and father begged their first-born son not to take monastic vows.

But in 1725, he secretly received a cassock with the name Hilarion from them in the Kiev Mezhyhirsky monastery, and on November 21, 1727, he was tonsured in a mantle with the name Joasaph in the Kiev-Bratsky Monastery. This event coincided with the completion of studies at the theological Academy. A year later, the monk Joasaph was ordained a hierodeacon by Archbishop Varlaam Vonatovich. He was left as a teacher at the Kiev Theological Academy. After the death of His Grace Varlaam, Archbishop Raphael Zaborovsky began to manage the Kiev department. Archbishop Raphael drew attention to the outstanding abilities of the young ascetic and attracted him to serve the Church more widely. He was entrusted with responsible obedience as an examiner at the Kiev Archdiocese. In November 1734, Archbishop Raphael ordained Hierodeacon Joasaph to the rank of hieromonk and transferred him from the collegiate Fraternal Monastery to the Kiev-Sofia Episcopal House. At the same time, he was appointed a member of the Kiev Ecclesiastical Consistory. While serving as an examiner, he put a lot of effort into correcting the moral shortcomings of the parish clergy. The consistorial position of the saint was an excellent school for his organizational abilities. During this time, he thoroughly studied the needs of the clergy, the advantages and disadvantages of the diocese. Here the comprehensiveness of Joasaph's business qualities was clearly defined, combined with great internal feats. He quickly ascended the ladder of spiritual perfection, as evidenced by his surviving work "The Battle of seven honest virtues with seven mortal sins."

On June 24, 1737, Hieromonk Joasaph was appointed rector of the Holy Transfiguration Mgar Monastery with the elevation to the rank of abbot. In his monastery, the abbot relied all his strength on the improvement of the monastery, which in the past was a stronghold of Orthodoxy in the fight against the union. The monastery contained the relics of St. Athanasius, Patriarch of Constantinople, Lubensky Wonderworker (memory of May 2). Several times Patriarch Athanasius appeared to Abbot Joasaph, testifying about his patronage.

In 1744, Metropolitan Raphael elevated Abbot Joasaph to the rank of Archimandrite. At the end of the same year, he was summoned to Moscow and soon, by order of the Holy Synod, was appointed vicar of the Holy Trinity Sergius Lavra. In the monastery of St. Sergius, he also selflessly fulfilled the obedience of the Church (in those years it took a lot of effort to restore the monastery after the fire).

On June 2, 1748, Archimandrite Joasaph was consecrated Bishop of Belgorod in the Peter and Paul Cathedral of St. Petersburg. Having entered the episcopal see, St. Joasaph strictly monitored the piety and condition of churches, the correctness of the performance of Divine Services, and especially the morality of the flock. The saint paid great attention to the education of the clergy, their correct observance of the charter and church traditions. As before, St. Joasaph devoted all his strength to the archpastoral ministry, not sparing his health. On the eve of his repose, the saint forbade his cellmate Stefan to seek holy orders and warned that in case of disobedience, he would suffer an untimely death. The saint pointed out to another cell-keeper, Vasily, that he would be a deacon, but he would never reach the rank of priest. And this prediction was subsequently fulfilled. On December 10, 1754, the saint passed away. The glorification of St. Joasaph in the face of saints took place on September 4, 1911.