A combat veteran of wars in Korea and Vietnam, he was awarded the Silver Star on three separate occasions for gallantry and heroism under fire. Coming from a long line of soldiers, his great-great-great-great grandfather, Thomas Maze, fought in the Revolutionary War, his grandfather served in the Union Army during the Civil War, his father was an Army colonel during World War II retiring after 37 years of military service, and his son is a retired lieutenant general with tours in Iraq and Afghanistan. Caldwell was born on July 20, 1925 at Fort Moultrie, South Carolina, into a military family. His father a soldier, and his grandfather fought for the Union Army in the American Civil War. Both of his parents were natural leaders and their home overflowed with friends associated with the military. Young Bill Caldwell basked in their camaraderie, emulated their character, and looked forward to the day when he could wear an officer's uniform. When Caldwell was 16, he lived with his family at Schofield Barracks, Hawaii. On December 7, 1941, the Caldwells were horror-struck as they heard the roar of Japanese planes attack Pearl Harbor and witnessed a Japanese plane strafe an officer running down their street. The next day, Bill helped at the base hospital and for the weeks that followed, drove an ammunition truck. Dependents were later evacuated from Hawaii; Bill, his mother, and his sister moved to Los Angeles where he finished high school. One of Caldwell's childhood dreams was to attend West Point, but he did not think he could get in and almost enlisted in the Marine Corps. He later said, "When the telegram came telling my family and me that I was accepted into West Point and I was to report there in two days or three days, I immediately caught a train out of El Paso and went to West Point." Commissioned as second lieutenant in the infantry in 1948, he attended ground general school at Fort Riley, Kansas and the Infantry School at Fort Benning in Columbus, Georgia. While in Columbus, he met his future wife Tudy Dismuke. Soon after their marriage, Second Lieutenant Caldwell was assigned to the 1st Battalion, 34th Infantry Regiment, 24th Infantry Division, which served as a Japanese occupation force on Kyushu. His unit was later deployed to Korea and was one of the first U.S. combat troops there. For heroism and gallantry in the Korean War, he was awarded two Silver Stars and a Bronze Star with Valor. After the Korean War, Caldwell served in a variety of command staff positions in the United States and Europe.