Johnson, the only man who attended initial meeting of both the General Baptist Missionary Convention (1814) and the Southern Baptist Convention (1845), was also the only man who served as president of each; he had a large part in the framing of constitutions for the two bodies. Johnson was the last southern president of the general convention (1841-44), and justified the confidence placed in him by his able leadership in reconciling opposing forces and thus delaying disruption of the convention. When separation became inevitable in 1845, Baptists of the South and Southwest turned to Johnson for counsel, and as first president of the Southern Baptist Convention (1845-51), he led in shaping its far-reaching program. From 1817 until his death, Johnson remained in South Carolina and was one of nine men who formed the South Carolina State Baptist Convention in 1821. Succeeding Richard Furman as president of the convention and serving for 27 years (1825-52), Johnson realized one of Furman's fondest dreams in helping found the school which became Furman University, out of which grew Southern Baptist Theological Seminary.