Civil War Union Army Officer. He was mustered in as 1st Lieutenant of Company G, 4th New Jersey Militia on April 27, 1861, soon after the Civil War began with the Confederate bombardment of Fort Sumpter, South Carolina. He served with his unit first in the defenses of Washington, DC, then in the July 1861 First Bull Run Campaign, where it was held in reserve. He was honorably mustered out on July 31, 1861, when the terms of the 4th New Jersey Militia's three-month enlistment expired by law. He was then commissioned into the 6th New Jersey Volunteer Infantry, being mustered in as 1st Lieutenant of Company G on September 9, 1861. In that duty he served for the next year, seeing action with his men at the May 1862 Battles of Williamsburg and Fair Oaks, the June 1862 Seven Days Battles, and the August 1862 Second Battle of Bull Run. The September 7, 1862 promoted of Colonel Gershom Mott, commander of the 6th New Jersey, to Brigadier General of Volunteers facilitated the advancement of a number of junior officers of the regiment. One of those effected was Company G's commander, Captain Theodore W. Baker. He was promoted to Major of the regiment on October 11, 1862, and Lieutenant Morris took over Company G. A month later, on November 17, 1862, he was was promoted to Captain. He led his troops for the next two years, as it and the regiment fought in the Battles of Chancellorsville, Gettysburg, The Wilderness, Spotsylvania, and Cold Harbor, and in the siege of Petersburg, Virginia. The regiment was dissolved in September 1862 when the original enlistments of the veterans expired, and the numbers of the re-enlistees and new recruits was not sufficient for the 6th New Jersey to continue. The remaining 6th New Jersey men were folded into the 8th New Jersey Volunteer Infantry in October 1864. Captain Morris, unlike a number of his fellow officers, found a place in the 8th New Jersey, and was given command of the unit's Company E. He commanded his troops through the conclusion of the conflict, seeing action in the last battles between the Union's Army of the Potomac and the Confederacy's Army of Northern Virginia in April 1865. After the Confederates had laid down their arms, Captain Morris received one more promotion. On April 15, 1865 he was commissioned as Major of the regiment, filling the vacancy when Major Henry Hartford was promoted to Lieutenant Colonel. Major Morris was finally mustered out of Federal service on July 17, 1865, having did his duty for the entirely length of the war.∼U.S., Registers of Deaths in the Regular Army, 1860-1889, page 110/111 shows:
Date of death: April 7, 1877
Name: Morris, Louis M.
Rank: 1st Lieut Bvt Maj
Company/Regt.: E/20th Inf.
Place of death: Lower Brulé Agency, D.T.
Cause of death: Congestive Apoplexy & Strangulation

Office of Acting Assistant Quartermaster,
Fort Snelling, Minn., July 9th 1877
To the
Adjutant General U. S. Army
Washington D. C.
Through Army Headquarters, Fort Snelling, Minnesota
Sir,
Under the provisions of General Orders No. 91, War Department, Adjutant General's Office of 1872, I have the honor to request the authority of the Honorable Secretary of War for the transportation by the Quartermaster Department of the remains of First Lieutenant L. M. Morris, 20th Infantry, from Lower Brulé Agency, D.T., the post at which he died April 7th 1877, to Philadelphia, Pa. It is the desire of Lieutenant Morris' widow that he be buried in Morristown, New Jersey, and she will arrange for the transportation from Philadelphia to that point.