Son of Ephrahim and Margaret Ann (Chapin) Fletcher.

Samuel was educated at Brown University and graduated in 1857.

On 12 Jul 1861 Samuel, an engineer, mustered into service with the 15th Massachusetts Volunteer Infantry as a Private. He was 30 years, 3 months and 12 days old.

James B. Fletcher, George F. Fletcher, along with Samuel, brothers, served together in the 15th Massachusetts Volunteer Infantry in Company H.

Samuel and George W. Davison, brothers-in-law, served together in the 15th Massachusetts served together in the 15th Massachusetts Volunteer Infantry.

On 18 Jul 1862 Samuel was promoted to 2nd Lieutenant. He was wounded shot through the jaw, but his remarkable constitution kept him alive on 17 Sep 1862.

On 17 Sep 1862 his brother, James Brainerd Fletcher, died at The Battle of Antietam, Washington County, Maryland, killed in action.

On 14 Nov 1862 Samuel was promoted to as a 1st Lieutenant.

He was wounded again while leading his men in the battle of Gettyburg on 3 Jul 1863 For his bravery he was presented with a sword by the regimental commander.

On 3 Jul 1863 his brother, George Fergo Fletcher, died at The Battle of Gettysburg, Adams County, Pennsylvania. On 4 Jul 1863 Samuel was promoted to Captain.

On 15 Aug 1863 his cousin, Edward Fletcher Chapin, died at Baltimore, Baltimore County, Maryland, of wounds at age 23.

On 9 Mar 1864 Samuel, 32, married Emma A. Luther, 23, daughter of Esek Luther, at Ashland, Middlesex County, Massachusetts, in a first marriage for both.

On 28 Jul 1864 Samuel ended military service with the 15th Massachusetts due to expiration of service term. He made application for a veteran's pension in Aug 1864.

He was a member of GAR Post # 78 (David A. Russell) in Whitman, MA, as well as of GAR Post # 163 (General J. G. Foster) in South Framingham, MA

He died on 11 Jul 1924 at Gill, Franklin County, Massachusetts. He was 93 years, 3 months and 11 days old.

From the "Springfield Republican," 15 Jul 1924:
Capt. Samuel Fletcher, Civil War Veteran had been honored for Bravery.
"Turners Falls, July 14 -- Capt. Samuel Fletcher, 93 years old, died suddenly at his home in Gill Friday morning. He was born in Bethel, ME., in 1830. He was graduated from Brown University in 1857 and soon after the Civil War began enlisted.
He made a remarkable record as captain of the 15th Massachusetts Regt. and was presented with a sword by the regimental commander in recognition of his bravery in the battles of Antietam and later at Gettysburg. He was wounded in both battles.
After the war he entered the state police department and served several years until he was elected representative to the Legislature from the town of Northbridge.
Mr. Fletcher went to Gill to make his home 12 years ago, and has been active in local affairs ever since.
He is survived by his widow and three daughters, Mrs. Walter Clapp and Mrs. Peleg W. Eddy of Gill, and Mrs. James E. Adams of Newton, also a son, Edward F. Fletcher of West Newton.
The funeral was held at the home Sunday afternoon, Rev. Thomas H. Vincent, pastor of the Congregational Church of Turners Falls officiated. The veterans of the Civil War and the Sons of Veterans attended the services in a body. Burial was in Sherburn."

In Aug 1924 Emma A. Luther received a pension.