When the Civil War broke out, McComb chose the Confederacy despite his Northern birth and enlisted as a private in the 14th Tennessee Infantry Regiment. Soon after his enlistment, McComb was elected second lieutenant, then major of his regiment.
When the American Civil War commenced, McComb opted for the Confederacy, despite his Northern origins, and enlisted as a private in the 14th Tennessee Infantry Regiment. Shortly thereafter, McComb was elected second lieutenant, then major of his regiment.