Willie was born on the 1st of January, 1890 in Breathitt County, Kentucky, and his mother died when he was young. He enlisted in the US Army in 1912 and was deployed in support of the Mexican Campaign in 1914. By the time he deployed to Europe in support of the Great War, Willie was a Sergeant with Company A, 132nd Infantry, 33rd Division, and his actions would earn him the Medal of Honor. The citation reads:

He showed conspicuous gallantry in action by advancing alone directly on a machine-gun nest which was holding up the line with its fire. He killed the crew with a grenade and enabled the line to advance. Later in the day he attacked alone and put out of action two other machine-gun nests, setting a splendid example of bravery and coolness to his men.

Willie was one of the seventeen men to have received the Medal of Honor in a ceremony at Chaumont, France from General Pershing on the 9th of February, 1919. He returned to Kentucky after the War where he and his wife Belvia raised their children. Willie Sandlin died at the age of 59 on the 29th of May, 1949, from an infection of the lungs that was a result of a poison gas attack during the Battle of the Argonne. He was the only Kentuckian to receive the Medal of Honor during World War 1 and was second to Sergeant Alvin York in regards to valor awards. His wife never remarried and she lived to be 96 years old and they were the first to be buried in the Kentucky Veterans Cemetery in Hyden, Kentucky: Section 2, Site 138.