Walter Gwynn was a Brigadier General in the Confederate Army during the American Civil War. In 1861, he was directed by Virginia governor John Letcher to assume command of the defenses around Norfolk and Portsmouth. He oversaw construction of defensive fortification at Sewell's Point, which was across the mouth of Hampton Roads from Fort Monroe at Old Point Comfort. In 1862, he participated in the Battle of Big Bethel during the Peninsula Campaign. In 1863, he was named comptroller of the State of Florida.
After the war, he returned to civil engineering in North Carolina. He died in 1882.