William Bullein Johnson was born on 13 June 1782 on Johnsí Island, S.C. near Charleston, to Joseph and Mary (Bullein) Johnson. He was educated at home in Georgetown, S.C. by his mother and by private tutors. His mother was of the Particular Baptist faith, believing that only some would be saved. As a child he met President George Washington and Dr. Richard Furman, pastor of the First Baptist Church Charleston, who made a great impression on him. He attended Brown University, receiving a degree in 1804. He had intended to become a lawyer, but was converted during a Baptist revival in 1804, and devoted the rest of his life to Christian service. He married Henrietta Hornby in 1803. One of their eight children who reached maturity, Francis C. Johnson, became a Southern Baptist missionary to China in 1846.
After preaching in several churches from 1804 to 1806, Johnson was appointed pastor of the Baptist church at Euhaw near Beaufort, South Carolina. In 1810 he was invited to become chaplain of South Carolina College, Columbia, and founded a Baptist church in Columbia. In 1811, he accepted an offer to become pastor of the Baptist church in Savannah, Georgia. It was here that Johnson met Luther Rice, who interested him in foreign missions, and whom he helped arrange the General Baptist Missionary Convention, or Triennial Convention, in 1814. He was one of the framers of the constitution of this convention.
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. He was also principal of the Greenville Female Academy, and founded a Baptist church in the town. In 1830, he moved to Edgefield to become principal of Edgefield Female Academy and pastor of Edgefield Baptist Church.
Johnson became the last southern president of the General Baptist Missionary Convention between 1841 and 1844. As tensions grew between the northern and southern Baptists over the issue of slavery, he attempted to avoid a split, but in 1845, he was asked to become the first president of the breakaway Southern Baptists Convention, serving until 1851. Towards the end of his life, he was chancellor of Johnson Female University, Anderson, South Carolina (1853-58). The Johnson Female Seminary opened in the village of Anderson in 1848. The school was forced to close during the Civil War and did not reopen. When Johnsonís health began to fail in 1858, he moved back to Greenville, S. C. to live with his daughter and her husband. He died on October 2, 1862.