Porter was transferred to the Army's Chemical Warfare Service in 1921 as a major. Porter graduated with distinction in 1927 from the
Command and General Staff School and then attended both the
Army Industrial College and the
Army War College. Porter served as Director of the Chemical Warfare School, located at the time in Washington, DC, and, as a colonel, as Chemical Officer, 9th Corps Area. After the outbreak of World War Two, Porter was appointed head of the Army
Chemical Warfare Service and promoted to major general. He led the service from May 1941 until 1945, despite having had no experience as a chemical officer in the First World War. Until March 1942, he reported directly to the Army Chief of Staff, but from then on to the Service of Supply, later renamed the
Army Service Forces. Porter was awarded the
Army Distinguished Service Medal for his wartime efforts. Porter retired from active duty on November 13, 1945. ==Publications==