He grew up to play Rugby League for Hull RLFC where he still holds the record for most tries scored in a single season, 52 in 1913/14. In total he scored 106 tries for the club, including one in the Challenge Cup Final win over Wakefield in 1914.
In 1915 he signed up for service with the East Yorkshire Regiment and was commissioned a second lieutenant in the 6th Platoon of the 11th Battalion - one of the "Hull Pals" Battalions.
On May 3rd 1917 the Hull Pals battalions went into action at Oppy near Arras in Northern France. Harrison's company found themselves pinned down in No-Man's Land by a machine gun nest at the edge of Oppy Wood.
After the company were pushed back Harrison single-handedly charged the gun and took it out of action with a Mills bomb. Tragically he was killed as he threw the bomb. For his heroic actions he was awarded a posthumous Victoria Cross.
This is the citation that describes the events in a little more detail
T/2nd Lt. John Harrison, M.C., E. York. R.
For most conspicuous bravery and self-sacrifice in an attack.
Owing to darkness and to smoke from the enemy barrage, and from our own, and to the fact that our objective was in a dark wood, it was impossible to see when our barrage had lifted off the enemy front line.
Nevertheless, 2nd Lt. Harrison led his company against the enemy trench under heavy rifle and machine-gun fire, but was repulsed. Reorganising his command as best he could in No Man's Land, he again attacked in darkness under terrific fire, but with no success.
Then, turning round, this gallant officer single-handed made a dash at the machine-gun, hoping to knock out the gun and so save the lives of many of his company.
His self-sacrifice and absolute disregard of danger was an inspiring example to all. (he is reported missing, believed killed.)
— London Gazette
Harrison's body was never recovered.
It is tempting of course to imagine Harrison making use of his Rugby League skills and pace to dodge across No-Mans land in the same way he evaded tacklers on the playing field. However there's no real need to romanticise an act of exception bravery and dedication to the men under his command.
Last weekend James, Nick and myself took a visit to Arras and Oppy Wood.
We first visited the Arras Memorial which records the names of 34,795 servicemen killed in the region who have no known grave. After a little searching we discovered Harrison's name, a little faded and timeworn in the East Yorkshire regiment bay.
Walking around the edge of the wood we were surprised to discover a memorial post marking the site of the machine gun nest.
The East Yorkshire regiment record of the action places the machine gun nest at the southern tip of the wood, which is where the post is placed.
After walking on around the wood we headed back toward Vimy ridge but on the journey drove past Orchard Dump cemetery. The Oppy Wood book suggests that Harrison's remains may have later been recovered and transferred to this cemetery. As with many First World War graves it contains a large number of unknown graves - perhaps his body does lie here.