 Feeling himself established, in November 1867 he married his sweetheart from his Richmond, Virginia, days, Constance Cary Harrison.In 1872 he was an envoy to Santo Domingo, Dominican Republic, with Samuel P. Samuels and T. Scott Stewart, to negotiate annexation with Buenaventura Báez.In 1875, Harrison became the secretary and counsel of New York City's Rapid Transit Commission.