James Johnson was born on June 19, 1843, in Pennsylvania to Rhodes and Catherine Johnson. His father died on November 11, 1847. He grew up and attended school in Scott, Pennsylvania, and by the late 1850s, Johnson and his brothers were reportedly “work[ing] out among the neighbors at farming” to help support their mother. He enlisted in the Union army on October 26, 1861, and mustered in as a private in Company H of the 76th Pennsylvania Infantry later that day. The army stationed the men in South Carolina, and he died in the attack on Fort Wagner on July 11, 1863.