Harding married in 1887 Justine Prindle Douglas, who was born on June 16, 1853, in New York City and died on February 6, 1909[1][unreliable source?]

in Washington, D.C. She was the daughter of Dr. John Hancock Douglas, an 1843 graduate of Williams College, and the University of Pennsylvania School of Medicine in 1847.

He was the personal physician for President Ulysses S. Grant, attending him from 22 October 1884, till the death of the latter, 23 July 1885.

The year of his deaconate was spent as an assistant to Henry M. Nelson Jr., rector of Trinity Church, Geneva, New York.

His formal appointment as the cathedral's first organist and choirmaster came in 1911 in anticipation of the opening of Bethlehem Chapel for services the following May.