Thomas F. O'Brien was born on November 15, 1910. In November 1942, Captain Thomas F. O’Brien was serving with Battery A, 7th Field Artillery Battalion, 1st Infantry Division, U.S. Army. On 8 and 9 November, CPT O’Brien’s unit was in action against enemy forces at La Zmacta, Algeria, during the Oran offensive. While on motor reconnaissance with his driver and radio operator, CPT O’Brien suddenly came under heavy enemy machine gun fire. When it became necessary to abandon his vehicle, CPT O’Brien ordered his two men to withdraw and remained to cover their withdrawal with his own small arms fire. CPT O’Brien's coolness and courage saved the lives of his two enlisted men and earned him the U.S. Army's third highest award for valor, the Silver Star Medal.

On 11 July 1943, CPT O’Brien was serving as Commanding Officer, Cannon Company, 16th Infantry Regiment, 1st Infantry Division, First U.S. Army, On that day, CPT O’Brien’s unit was in action against German forces at Gela Beach, Sicily. When his 16th Regiment was under a savage attack by a strong force of German armor, causing a critical threat to the invasion effort, CPT O’Brien placed himself in an exposed position 500 yards from the oncoming tanks to better direct the fire of his Cannon Company. Exhibiting amazing courage in the face of almost certain death, CPT O’Brien remained at his shell-hammered post for a day and a half. CPT O’Brien's actions resulted in the destruction of 19 German tanks and wheeled vehicles, and turned a serious threat into a strong victory. CPT O’Brien’s courageous actions and extraordinary heroism that day earned him the U.S. Army's second highest award for valor, the Distinguished Service Cross.

On D-Day, 6 June 1944, CPT O’Brien's unit landed on Omaha Beach at Normandy, France. The 1st Infantry Division and one regimental combat team from the 29th Infantry Division comprised the first wave of troops that assaulted German Army defenses at Omaha Beach. Severe casualties were inflicted on CPT O’Brien’s Cannon Company when the craft on which they were coming ashore was hit and sunk. Upon reaching the shore, CPT O’Brien found that his men were scattered and disorganized. Despite the fact that most of the men were pinned down by extremely heavy German fire, CPT O’Brien ignored his own safety and moved up and down the fire-swept beach shouting orders and giving encouragement to the men. By his calm leadership, CPT O’Brien successfully reorganized his Cannon Company. When he saw that several tanks were buttoned up and not firing, CPT O’Brien quickly worked his way through the heavy enemy fire to them, found their crews, and led them up the beach to a point from which they could engage the German guns. CPT O’Brien’s inspiring leadership, courageous actions and extraordinary heroism that day earned him a Bronze Oak Leaf Cluster in lieu of a Second Award of the Distinguished Service Cross.

On 16 November 1944, CPT O’Brien was Killed in Action during the Battle of Hürtgen Forest. He is now buried in Riverside Cemetery, Lincoln, Grafton County, New Hampshire, USA.

Distinguished Service Cross Citation (1st of 2 Awards)
The President of the United States of America, authorized by Act of Congress July 9, 1918, takes pleasure in presenting the Distinguished Service Cross to Captain (Infantry) Thomas F. O'Brien (ASN: 0-357647), United States Army, for extraordinary heroism in connection with military operations against an armed enemy while serving as Commanding Officer, Cannon Company, 16th Infantry Regiment, 1st Infantry Division, in action against enemy forces on 11 July 1943, at Gela Beach, Sicily. When his regiment was being savagely attacked by a strong force of enemy armor, causing a critical threat to the invasion effort, Captain O'Brien, with absolute disregard of his personal safety, placed himself in an exposed position five hundred yards from the oncoming tanks to better direct the fire of his Cannon Company. Captain O'Brien, exhibiting magnificent courage in the face of almost certain death, remained at his dangerous, shell-hammered post for a day and a half. His exemplary actions resulted in the destruction of nineteen enemy tanks and wheeled vehicles, and turned a serious threat into a glorious victory. His heroic and fearless behavior under adverse circumstances were an inspiration to his men, and reflect the highest traditions of the Service.
Headquarters, First U.S. Army, General Orders No. 17 (1944)

Distinguished Service Cross Citation (2nd of 2 Awards)
The President of the United States of America, authorized by Act of Congress, July 9, 1918, takes pleasure in presenting a Bronze Oak Leaf Cluster in lieu of a Second Award of the Distinguished Service Cross to Captain (Infantry) Thomas F. O'Brien (ASN: 0-357647), United States Army, for extraordinary heroism in connection with military operations against an armed enemy while serving as Commanding Officer, Cannon Company, 16th Infantry Regiment, 1st Infantry Division, in action against enemy forces on 6 June 1944, in France. Captain O'Brien landed on the coast of France with the initial assault wave. Severe casualties were inflicted on his company when the craft on which they were coming ashore was hit and sunk. Upon reaching the shore, he found that his men were scattered and disorganized. Despite the fact that most of the men were pinned down by extremely heavy enemy fire, Captain O'Brien, disregarding his own personal safety, moved up and down the fire-swept beach shouting orders and giving encouragement to the men. By his valiant leadership, he successfully reorganized his company. When he observed that several tanks were buttoned up and not firing, he immediately worked his way through the heavy enemy fire to them, found their crews and led them up the beach to a point from which they could engage the enemy guns. Captain O'Brien's inspiring leadership, personal bravery and zealous devotion to duty exemplify the highest traditions of the military forces of the United States and reflect great credit upon himself, the 1st Infantry Division, and the United States Army.
Headquarters, First U.S. Army, General Orders No. 42 (August 6, 1944)

Source of information: www.findagrave.com, http://www.militaryhallofhonor.com/honoree-record.php?id=315325