Archbishop Nikitas studied at Florida University where he earned a Bachelor of Arts with Honours in 1976. He then enrolled at Holy Cross Greek Orthodox School of Theology, graduating in 1980 with a Master of Divinity with Honors.

Following his ordination to the priesthood, he was assigned as the Associate Pastor at Saints Constantine and Helen Greek Orthodox Cathedral in Merrillville, Indiana. In 1987, he became the Chancellor of the Greek Orthodox Diocese of Chicago, Illinois, and at this same time, he also served as a Lecturer in Orthodox Theology at Loyola University.

He was elected Metropolitan of Hong Kong and Southeast Asia in 1996. While in Hong Kong he also served as a Lecturer in Orthodox Theology and Liturgy at the Holy Spirit Catholic Seminary from 1999-2007.

Archbishop Nikitas serves the Mother Church in Constantinople in numerous important areas including: Coordinator of the Patriarchal Task Force on Human Trafficking and Modern-day Slavery; Chairman of the Committee on Youth for the Ecumenical Patriarchate; and Co-Chair and Steering Committee member of the Elijah Inter-Faith Foundation. 

His Eminence Nikitas was elected Archbishop of Thyateira and Great Britain on 12 June 2019. 

On 19 June 2023, His Eminence was voted President of CEC.