Harold was born in Masbrough and attended Kimberworth Central School. He then worked at Tinsley Rolling Mills and was a well known member of the Rotherham Harriers.
Shortly after joining the army he volunteered for airborne forces. Sergeant Wilmott was on parachute training course number 10 at RAF Ringway. The course lasted from 16th - 27th March 1942. Upon successful completion of the course, Sgt Wilmott was posted to 10 Platoon, C Company, 4th Parachute Battalion.
Whilst serving with this unit, Sgt Wilmott saw action in North Africa (Op Torch), Italy, Southern France (Op Dragoon) and Greece (Op Manna). Whilst fighting in Greece, Macedonia he was attacked by machine guns. He suffered nine bullet wounds in his face, neck, shoulder, arm and leg.
During the Second World War, Sgt Wilmott was awarded two Military Medals. His first was awarded 1943 in Italy. His citation reads:
"Sgt. Wilmott has been a section Pl Sgt throughout the Bn campaign in Italy and has shown continuous courage and devotion to duty throughout the period taking part in many patrols against the enemy when, by his dash and initiative he has inflicted casualties upon the enemy and taken prisoners. On the Ossoqua Sector 20th December 1943-3rd Jan 1944Sgt. Wilmott's Pl was in an isolated position on the Cheamats feature where he took several patrols against the enemy on one occasion with two others bringing back 7 German prisoners. In the Cerielle Sector 5th Jan 1944 - 19th Feb 1944 Sgt. Wilmott again led offensive patrols against the enemy and on Jan 30th led his Section in an assault on an enemy position inflicting casualties and bringing back a prisoner urgently demanded by the army. At all times his resource and aggressive spirit in action has been of the highest order."
Sergeant Wilmott's second MM was awarded to him for his actions at Les Serres in August 1944. His citation reads:
"On the 15th of August 1944 at Les Serres, near Le Muy, Sjt Wilmott was Pl Comd of No 10 Pl. His Officer has been killed and the Pl was ordered to take part in a Coy attack on the enemy defended positions around the bridges at Les Serres, evolving approach over open country, crossing wire obstacles and scaling of walls from 5 to 12 feet high, loop holed. Sjt Wilmott lead his men with great dash and courage and when the Pl came under accurate MG fire he moved forward and destroyed the post. He was first over the wire and walls and knocked out another MG post and then led the attack on the houses within the defenses, where he killed another German bringing his personal total to 5 enemy killed. His example and total disregard for his own safety was an inspiration to his Company."
After the war he decided to emigrate to Australia with his wife and four children.