Shannon was promoted to Colonel in May 1942. He was awarded the Navy Distinguished Service Medal for his leadership of the 6th Defense Battalion during the Battle of Midway (4 June 1942 – 7 Jun 1942).
Shannon was elevated to Colonel in May 1942. He received a high honor for his command of the 6th Defense Battalion during the Battle of Midway from June 4 to June 7, 1942.