 He was one of five Irish MPs who served with British army Irish brigades, J. L. Esmonde, Stephen Gwynn, William Redmond and D. D. Sheehan being the others, as well as former MP Tom Kettle.Redmond was commissioned as a captain in the 6th Royal Irish Regiment in February 1915 at the age of 53, with whom he previously had served 33 years before.After refresher training in the New Barracks, Fermoy, he went out to France on the Western Front with the 16th (Irish) Division, composed of Irish volunteer troops, under the command of Major-General William Hickie, in the winter of 1915–16.