 First enlisting in the artillery in 1864, Boyne served with B Battery of the Second Colored Light Artillery in battles around Richmond (Wilson's Wharf and City Point, Virginia) during the Civil War in 1864.He was discharged in March 1866 near Brownsville, Texas, and ten months later, joined the 40th Infantry under the name Thomas Bowen.The 40th Infantry consolidated into the 25th Infantry, in which he served until 1875.