Ward was born in Wanganui, where he attended Wanganui Technical College. He trained as a teacher at the Wellington College of Education in 1938, and taught until enlisting in the Royal New Zealand Air Force on 2 July 1940. He trained as a pilot at Taieri and Wigram with Fraser Barron, who went on to become a renowned bomber pilot during the war. Barron and Ward sailed together on the Aorangi in January 1941 and were both stationed at 20 OTU Lossiemouth, in Scotland.
Ward was a 22-year-old sergeant pilot with No. 75 (NZ) Squadron when he carried out the action for which he was awarded the Victoria Cross . He was co-pilot on a Vickers Wellington bomber flying out of RAF Feltwell in Norfolk, United Kingdom. On 7 July 1941 after an attack on Münster, Germany, the Wellington in which Sergeant Ward was second pilot was attacked by a German Bf 110 night fighter. The attack opened a fuel tank in the starboard wing and caused a fire at the rear of the starboard engine.
The skipper of the aircraft told him to try to put out the fire. Sergeant Ward crawled out through the narrow astrodome on the end of a rope initially reported as being taken from the aircraft's emergency dinghy, but actually from an engine cover. He kicked or tore holes in the aircraft's fabric with a fire axe to give himself hand- and foot-holes. By this means he reached the engine and attempted to smother the flames with a canvas cover.
Although the fuel continued to leak, with the fire out the plane was now safe. His crawl back over the wing, in which he had previously torn holes, was more dangerous than the outward journey but he managed with the help of the aircraft's navigator. Instead of the crew having to bail out, the aircraft made an emergency landing at Newmarket, United Kingdom.
In the summer of 1941, Sergeant Ward was summoned to 10 Downing Street by Prime Minister Winston Churchill. The shy New Zealander was struck dumb with awe by the experience and was unable to answer the Prime Minister's questions. Churchill regarded the reluctant hero with some compassion. "You must feel very humble and awkward in my presence," he said. "Yes, sir," managed Ward. "Then you can imagine how humble and awkward I feel in yours," said Churchill.
James Ward was killed in action on 15 September 1941, when his Wellington bomber was hit by flak over Hamburg, caught fire and crashed. Only two of the five crew survived. It was Ward's 11th sortie, and his 5th as crew captain. He is buried in the Commonwealth War Grave Cemetery Ohlsdorf in Hamburg.
On 14 May 2011, the community centre at RAF Feltwell was dedicated in his honour.