Father Demetrios N. Treantafeles was born on March 9, 1927 in Alea, Tegeas, Greece.

He attended local schools and transferred to the Ecclesiastical School of Corinth, where he studied Byzantine Church Music and Pastoral Theology. Father Demetrios came to the United States in 1947. He pursued studies in theology at the Holy Cross Greek Orthodox School of Theology in Brookline, Massachusetts, and graduated in 1952.

Father Demetrios and Presvytera Rose, daughter of William and Christine Chakos, were married in July, 1952. Father Demetrios was ordained to the Priesthood on September 21, 1952, and he has contributed faithfully in each community he served.

His first assignment was at Saint Nicholas Church in Chicago, Illinois, from 1952 to 1956.

He organized the Sunday School program, the choir, and adult Bible Class sessions. From there, he was assigned to the Church of the Annunciation in Kansas from 1956 to 1965 where he represented the Archdiocese in various interfaith meetings and appeared on local television stations regarding our faith. He served on various committees on race and religion and also lectured at colleges and universities.

He was then transferred to the Church of Saint John the Baptist in Des Plaines, Illinois until 1969. During his ministry at Saint John, the foundation of the community became stronger in the areas of culture and education.

His next assignment was at the Assumption Church in Chicago, Illinois from 1969 to 1981. He served this community in its most critical period of development. He was the Director of the Religious Education Department of Plato School and was also the producer and director of a weekly religious education program, the "Voice of Assumption". During this period the church was also refurbished.

In 1981, he was assigned to the Church of Saint Nectarios in Palatine, Illinois. He came to this community bringing life and zeal in his services. At Saint Nectarios Church, as well as in every community he has served, Father has brought and emphasized love, fellowship, unity and healing. On June 20, 1982, ground was broken for a new church building and on June 19, 1983, its doors were opened. Father Demetrios proceeded to embark upon the embellishment of the church, and also upon the construction of the community center. Completed in September of 1989, the community center served the educational and fellowship needs of the parish. The furnishing and beautification of the church, especially its iconography, was completed in phases, with the final completion in the spring of 1995. Under Father Demetrios' spiritual leadership and guidance, the church grew to 700 stewards. On September 24, 2000, a grateful community and its devoted priest received the greatest blessing, the consecration of the Church of Saint Nectarios.

Father has led four pilgrimages to the Holy Land and Egypt for the spiritual enrichment of the faithful. He is the founder of the GSL, Greek as a Second Language Program, a program for children from homes where Greek is not spoken.

Father introduced congregational singing, especially during weekday services. For many years, Father was a regular contributor to "The Greek Press", with a column, "Μεταξ? Μ?ς" ("Between Us"), a series of sermons of a contemporary nature, and now a regular contributor to "The Hellenic Tribune".

Since Father Demetrios' official retirement in 2001, he has tirelessly responded to the call of the Church, often traveling long distances to various communities in Illinois and Wisconsin, assisting and meeting the needs of his younger fellow clergymen. Remembered and loved by so many of the faithful he served for five decades, he continues to respond to their requests for counseling and to their pleas to participate in the baptisms, Weddings, and most frequently, in the funerals of their loved ones. Father Demetrios also continues to visit and counsel the residents, often on a daily basis, at the Greek American Rehabilitation and Nursing Home in Wheeling, Illinois.

For over fifty-five years, with fatherly concern and love, Father Demetrios, affectionately also known as Father T, has served the Church and her people. He continues to do so today. Father Demetrios and his beloved Presvytera Rose reside in Mt. Prospect, Illinois and have a son Nicholas, a daughter Maria, and four grandchildren, Demetrios, Christina, Nicholas, and Athanasios, children of Nicholas and his wife Joan.