Initially, William Hall simply wanted to enter the military police, but his entry tests showed him to be a strong candidate for ACU training. He decided to become an ACU commander and graduated at the top of his class.
After a career spanning decades, Hall was promoted to Lieutenant General in the waning days of the Infinite War, becoming the second-highest ranked officer in the UEF. After the Seraphim attacked (and President C. Allen Riley II was killed), Hall assisted General Samantha Clarke with running all aspects of the UEF.
With the death of Clarke, Hall assumed full command of the UEF. His primary goal is the preservation of humanity, regardless of faction identity or past grievances. To that end, he is a strong proponent of the three factions--UEF, Aeon and Cybran--forming a permanent alliance.
In Forged Alliance, Hall is voiced by Keith Szarabajka.