 In 1778 Doak settled in Tennessee in Sullivan County and was ordained a Presbyterian minister.Moving to the Holston valley in Tennessee, Doak assumed the Presbytery's charge to serve the congregation of the Fork Church, now known as New Bethel Presbyterian Church.In 1780, Doak relocated from Sullivan County and to the western section Washington County near present-day Limestone, Tennessee, where he formed where he founded Salem Presbyterian Church, built a home, and constructed a school.