He fought at the First Battle of Bull Run, afterward was engaged until 1862 upon the defenses of Washington, D.C.. He then commanded the Engineer Brigade during the Peninsula Campaign and the Northern Virginia Campaign, as well as during the Battle of Antietam.
During the First Battle of Bull Run, he engaged in combat.  He continued to defend Washington D.C. until 1862. Subsequently, he led the Engineer Brigade during the Peninsula Campaign and Northern Virginia Campaign, including the Battle of Antietam.