Son of Allegheny Cemetery Manager, Reuben Miller Jr. and Anna Mills, a Pittsburgh native and a grocer in civilian life, Joseph L. Miller was grievously wounded in action on July 3, 1863 at the Battle of Gettysburg in service with Hampton's famous Battery B. This unit famously repulsed Pickett's charge and held the confederate high water line. A prominent monument memorializing Battery B stands at this location in Gettysburg National Military Park and lists their names, with Miller in center. His injuries were deemed mortal immediately, though he survived long enough to be transferred at home to Pittsburgh, where he succumbed on August 9th of that summer at age 22. He was remembered by his comrades as "a brave and gallant soldier, always at his post, and by his gentle and pleasing manners endeared himself to all members of the Battery."