A longtime National Guard member, Watres was a veteran of the Pancho Villa Expedition and World War I, and received the Distinguished Service Cross for wartime heroism during combat in France.

During his Congressional service, Watres largely concentrated on veterans' issues and the regulation of the growing air mail and commercial aviation fields.

[2] In March 1899, Watres joined the Pennsylvania National Guard's Company K, 11th Infantry Regiment as a private, and he served until being discharged in November 1899.

[3] In October 1907 he joined Company H, 13th Infantry Regiment as a private, and he advanced to corporal and sergeant before receiving his commission as a second lieutenant in July 1908.

[4] As a captain, Watres commanded Company C, 13th Infantry Regiment during its service on the Mexico–United States border as part of the Pancho Villa Expedition.

[5] During action near Baslieux-lès-Fismes, Watres took the initiative to assume command of Company D, 109th Infantry, which had lost all its officers and was falling into disorganization.

[8] 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) Laurence H. Watres, United States Army, for extraordinary heroism in action while serving with 108th Machine-Gun Battalion, 28th Division, A.E.F., near Baslieux, France, 5 September 1918.

Under heavy enemy machine-gun fire, Captain Watres took command of Company D, 109th Infantry, which was without officers and was greatly disorganized in a position to his rear.

He led the company, together with some of his own men to the attack, killing a number of the enemy, taking others prisoners, and capturing several machine gun nests.

[2][10] For many years he was corporate counsel and a board of directors member of Scranton's Spring Brook Water Company, another Watres family venture.

[12] Watres was involved in numerous charitable and civic endeavors, including service as executive officer of the Order of DeMolay in Pennsylvania from 1939 to 1951.

[2] In addition, he served as a trustee and president of the Community Welfare Association of Scranton and Dunmore, which later became the Lackawanna United Fund.

[2] His service in the U.S. House was largely concerned with veterans' issues and the development of air mail and commercial aviation.