Born in The Grove, Lymington, Hampshire, England, Harding was an officer in the 22nd Foot (Cheshire Regiment) and was promoted to colonel in 1858. He was transferred from Malta to New Brunswick in 1866 and was appointed commanding officer. As the senior military officer, he was recommended by Charles Hastings Doyle for the position of Lieutenant Governor of New Brunswick and was appointed in 1867. In 1868, he was promoted to the rank of major general and returned to England in 1869.