[19] Through his mother, he was a great-grandson of pioneer Baptist clergyman George Washington Baines, who pastored eight churches in Texas, as well as others in Arkansas and Louisiana. Baines was also the president of Baylor University during the American Civil War.[20]
Johnson's grandfather, Samuel Ealy Johnson Sr., was raised as a Baptist and for a time was a member of the Christian Church (Disciples of Christ). In his later years, the grandfather became a Christadelphian; Johnson's father also joined the Christadelphian Church toward the end of his life.[21] Later, as a politician, Johnson was influenced in his positive attitude toward Jews by the religious beliefs that his family, especially his grandfather, had shared with him.[22] Johnson's favorite Bible verse came from the King James Version of Isaiah 1:18 "Come now, and let us reason together ..."[23]
Johnson grew up in poverty, with his father losing a great deal of money.[24] Biographer Robert Caro described him as being raised "in a land without electricity, where the soil was so rocky that it was hard to earn a living from it.