Nelson was ordained as a deacon by Maryland's bishop
Pinkney in 1875. He was ordained to the priesthood by Bishop
William Bacon Stevens of
Pennsylvania in 1876. Nelson served as rector of the Church of St. John the Baptist in what became Philadelphia's
Germantown neighborhood (1876-1882), then accepted a position as rector of
Cathedral Church of the Nativity in
Bethlehem, Pennsylvania (1882-1892), then in the
Episcopal Diocese of Central Pennsylvania but since 1904 the cathedral of the
Episcopal Diocese of Bethlehem. After two higher profile churchmen refused to accept offers to lead the
Episcopal Diocese of Georgia, Nelson accepted the offer made to him. He was consecrated as Bishop on February 24, 1892, in St. Luke's Church, Atlanta, by bishops including
Charles Todd Quintard of Tennessee,
William B. W. Howe of South Carolina and
Theodore B. Lyman of North Carolina as well as bishops Whitehead, Rulison, Coleman, Jackson and Watson. Nelson served as Bishop of the
Episcopal Diocese of Georgia until its split into two dioceses in 1907, when he chose to become the first bishop of the
Episcopal Diocese of Atlanta. As bishop, Nelson had challenged the Diocese of Georgia to grow, and it did. From 1893 until 1906, the diocese grew from 88 missions to 108 missions, and its 6,292 communicants of 1893 swelled to 9,229 by 1906. During that same time period, sixty-two church buildings were built in the diocese. Nelson also supported African Americans within his diocese to the extent permitted by social mores, consecrating the first and only African American deaconess,
Anna Alexander, in 1907. Addressing the second annual meeting of the diocese's council of colored churchmen at the Church of the Good Shepherd, he described Alexander as "a devout, godly and respected colored woman," and ordained her as a
deaconess (she would become the Episcopal Church's first and only African American deaconess). At the time of the diocesan separation later that year, the Diocese of Atlanta (northwestern Georgia) was created with 28 churches and missions. The remaining Diocese of Georgia consisted of 24 churches (including deaconess Alexander's Church of the Good Shepherd). Nelson's publications included collections of
Episcopal Addresses and
Occasional Sermons, as well as editorial articles in
The Church in Georgia. ==Death and legacy==