[3] In 1863, the age of 14, Harrison enlisted in the Confederate Army to fight in the American Civil War.

[2][3] Harrison served until the end of the war, obtaining the rank of Sergeant, and twice refusing further promotion.

[6] In that session Harrison helped the effort to pass a bill to establish an industrial college for female students (now the Mississippi University for Women), which was located in Columbus due to his influence.

[3][6] After serving in the House, Harrison temporarily retired from politics to focus on his law career.

[1][6] He was a Grand Commander and Knight Templar in the Masonic Order and also belonged to the Odd Fellows.