Civil War Confederate Spy. He is best remembered for providing Confederate Lieutenant General James Longstreet with valuable information concerning the movement of Union forces who were following the Confederate Army on their second invasion of the North, which ultimately led to the Battle of Gettysburg in Pennsylvania. Prior to the Civil War he aspired to become an actor but received very few leading parts due to his small stature. When the Civil War broke out in April 1861 he joined the Mississippi State Milita as a private but was discharged in November of that year and was eventually recruited as a spy by Confederate States of America Secretary of War, James Seddon. He met Longstreet in April 1863 at the Battle of Suffolk (or Battle of Fort Huger) in Virginia, and soon began providing him with reliable information on the enemy's positions, for which he was paid for his services in US gold coins or greenbacks. After Confederate successes at the Battle of Fredericksburg in December 1862 and the Battle of Chancellorsville in late April-early May 1863, Confederate General Robert E. Lee decided to embark on an invasion of the North in mid-June of that year. On June 28, 1863 Harrison informed Longstreet and Lee about the advancement of Union positions from Frederick, Maryland, who were in pursuit of the Confederate forces. As a result of his information, Lee concentrated his forces near Gettysburg, Pennsylvania and engaged the Union Army beginning on July 1, 1863 and ending on July 3, which resulted in a major victory for the North. After the battle he married and relocated to New York City, New York and continued his spy operations there, but none of his achievements were as significant as his discovery shortly before the Gettysburg engagement. When the Civil War ended he took his family to Mexico but marital difficulties led him to leave Mexico in 1866 and travel to the Montana Territory to prospect for gold. From 1867 to 1892 his whereabouts remained unknown and his wife remarried, assuming that he was dead. In 1893 he appeared in Cincinnati, Ohio, obtaining a job there in 1901 as a detective for the Municipal Reform League. He then moved across the Ohio River to Covington, Kentucky in 1912 and applied for a Confederate pension, where he died 9 years later at the age of 91. He was a major character in Michael Shaara's historical novel "The Killer Angels," and was played by actor Cooper Huckabee in the film version "Gettysburg."