Edmund Rice was commissioned lieutenant-colonel on July 2, 1864 and commanded his regiment in the Rapidan Campaign of the Army of the Potomac, and the battles of Bristoe Station, Blackburn's Ford, Robinson's Cross Roads and Mine Run.

In April, 1864, on the occasion of the review of the different corps of the Army by General Grant, the 19th Massachusetts Volunteers, Lt.-Colonel Edmund Rice commanding, was selected by General Meade, as his was one of the two best drilled and disciplined regiments in the Army of the Potomac, to drill before General's Grant,Meade, and Sheridan, and the Corps Commanders.

He commanded his regiment in the battle of the Wilderness, May 5-7, 1864, and Laurel Hill, May 8, 1864. He was wounded and captured in the assault at the "Death Angle" Spotsylvania, May 12, 1864. In North Carolina while being conveyed South, he escaped by cutting through the door of a freight car in which the prisoners were confined and jumping from it, while the train was under full headway. He reached the Union lines, near the Ohio River, after travelling twenty three nights (resting by day) having walked between three and four hundred miles.

He was commissioned colonel in July 1864, but not mustered owing to the heavy casualties which had reduced his regiment below the standard required by the War Dept. for the mustering of colonels.Yet he acted as colonel until the close of the war.

He rejoined his regiment in front of Petersburg in August 1864; was in command of Fort Rice and engaged in the battles of Second Deep Bottom, Weldon Railroad, Ream's Station and Second Hatcher's Run; in command of Fort Steadman and Batteries Eleven and Twelve in front of Petersburg. He was present at the surrender of the Confederate Army at Appomattox Court House; was mustered out in Virginia on June 30, and the regiment disbanded at Readville, Mass, July 20, 1865.

Edmund Rice received three brevets in the U.S. Army in 1866- Brevet Captain U.S. Army, for gallant and meritorious services at the battle of Antietam, Md. Brevet Major U.S. Army, for gallant and meritorious services at the battle of Gettysburg, Penn. Brevet Lieutenant-Colonel U.S. Army, for gallant and meritorious services at the battle of the Wilderness, Va.

He served in the U.S. Army until 1903, when he retired with the rank of Brigadier General.