Archbishop Kyrill was born Ilia Yonchev, the son of Mancho and Anna Yonchev, on February 26, 1920 in the historic city of Panaguriste, Bulgaria. He graduated from the Saint John of Rila Theological Seminary in Sofia in 1940.
On January 19, 1941, he was tonsured to monastic orders and given the name Kyrill. The following day, he was ordained to the diaconate. In April 1943, he was ordained to the holy priesthood.
Father Kyrill graduated from the Saint Clement of Ochrid School of Theology in 1944, and was appointed instructor of theology in the seminary in Plovdiv, Bulgaria. In the same year, he was named abbot of the Bachkovo Monastery where, during World War II, he and other leading civic and religious leaders helped protect Bulgaria's Jewish population from extermination at the hands of the Nazi occupiers.
In 1946, Father Kyrill was sent to Bern, Switzerland, for advanced studies in theology and philosophy. In 1950, following the communist takeover of Bulgaria, he emigrated to the United States. A short time later, he was assigned pastor of Saint George Bulgarian Orthodox Church, Toledo, OH.
On December 6, 1959, Father Kyrill was elevated to the rank of archimandrite, and in 1963, he was named administrator of the Bulgarian Diocese in the United States. On August 9, 1964, he was consecrated Bishop of Toledo and Toronto and the Bulgarian Diocese of the United States of America and Canada.
On December 20, 1976, Bishop Kyrill united the Bulgarian Diocese to the Autocephalous Orthodox Church in America. In October of the following year, he was appointed locum tenens of the Pittsburgh Archdiocese, and in 1978, he was chosen ruling hierarch of the Archdiocese of Pittsburgh and Western Pennsylvania, a position he held for 29 years. He also continued to serve as the ruling hierarch of the OCA's Toledo-based Bulgarian Diocese. In 1992, he was elevated to the dignity of Archbishop by the Holy Synod of Bishops of the Orthodox Church in America.
Archbishop Kyrill was the senior hierarch of the Holy Synod of the Orthodox Church in America. He was a member of the Lesser Synod of Bishops and served on numerous Church committees, including the Canonization Commission and the Board of Theological Education. He also was a trustee of Saint Vladimir?s Orthodox Theological Seminary, Crestwood, NY, and a member of the executive council of the Christian Associates of Southwestern Pennsylvania.