John Halliday Patrick was born on March 11, 1820, in Edinburgh, Scotland. Before the war he was a tailor in Cincinatti, Ohio.
On April 25, 1861 Patrick became lieutenant colonel of the 5th Ohio Infantry Regiment when it was formed for ninety days service. He continued in the same rank when the regiment reformed for three yards service in June of 1861. On August 2, 1862 he was promoted to colonel. He was in command of the 5th Ohio at the Battle of Cedar Mountain, missed the Battle of Antietam due to illness, and commanded at the Battle of Gettysburg (see regimental monument at Gettysburg).
From November of 1863 until January of 1864 during the Atlanta Campaign he commanded the First Brigade of the Second Division of the Twelfth Corps.
Patrick was killed at the Battle of New Hope Church, Georgia, on May 25, 1864, struck in the abdomen by an artillery shell. He is buried in the Wesleyan Cemetery in Cincinatti, Ohio.