[3] Oh and his wife, Pearl, were teachers in the Philadelphia area before moving to Deerfield, IL for seminary training at Trinity Evangelical Divinity School.
It was there while under the training of Paul Hiebert, that they received a call to global mission with a particular vision for reaching Japan with the gospel.
In 1998 and 1999 they served as missionaries with Mission to the World in Nagoya, Japan where they planted Chita Zion Church, founded the Open House English School, and began an outreach event for young people called Heart & Soul.
[6][7] Oh first became involved with the Lausanne movement by participating in the 2004 Forum for World Evangelization in Pattaya, Thailand.
His parents, Sung Kyu Henry and Young Lee Oh, along with his older sister Tina, immigrated from South Korea to America in 1970.