Bishop John T. Leslie Jr. was born in Macon, Georgia to John Thomas Leslie, Sr. and Essie (Fields) Leslie. At the tender age of 9, John Leslie, Jr. was baptized in the name of Jesus Christ and was filled with the Holy Ghost under the leadership of the Church of Jesus Christ's (COJC) founder, the late Pastor Lena Sears. It was at this age when he dedicated his life to the ministry of Jesus Christ. By the time he was 15 years old, he began teaching Sunday School classes. At the age of 16, he began preaching the Gospel of Jesus Christ. He held his first revival in Atlanta, Georgia at the age of 17, and at the age of 18, he received his first Ministerial License from the Pentecostal Churches of the Apostolic Faith, Inc. (PCAF). During his college career, Elder John Leslie began to evangelize across the United States.

In 1965, he earned a Bachelor of Arts degree in Business Administration from Howard University. He also pursued a graduate degree in Business Management at American University, but it was at Central Michigan University in Mt. Pleasant, Michigan, where he earned his Masters in Business Management. He also earned his Doctorate of Theology from the Pentecostal Bible College in Tuskegee, Alabama.

Elder John Leslie became an ordained Minister in August 1967 at the PCAF National Convention. Since that time, Bishop Leslie has served the PCAF in several capacities: the current Assistant Secretary of the PCAF; Bishop of the 6th Episcopal District, Secretary of the Board of Directors, Chairman of the Auditing Committee, and Treasurer of the National Youth Conference Currently, Bishop Leslie is the General Treasurer of the P.C.A.F.

Bishop Leslie is the current Diocesan Bishop of the Eastern and Southern States Council (ESSC). Formerly, he was the ESSC's Treasurer and Chairman respectively, of the parent body, field-worker, secretary, and chairman of the Young People's Department's.

Bishop Leslie has been pastoring the COJC since 1980. Bishop Leslie ministers weekly on three radio broadcast stations: WYCB 1340 AM in Washington, DC; WFTH 1590 AM in Richmond, VA, and WNAP 1110 AM in Philadelphia, PA.

Bishop Leslie has been married for more than 40 years to Louise (Moore) Leslie. From this union, they are blessed with five (5) children: Monique (Leslie) Yancy; John Thomas, III, Teresina (Leslie) Chin, Philip, and Stephen Thaddaeus, Sr.; two sons-in-law; three daughters-in-law; and nine (9) grandchildren.