Ernest Seaman was born on 16 August 1893, in the village of Heigham, near Norwich, to Henry and Sarah Seaman, who already had a daughter. His father died while Seaman was still a child but his mother was later remarried, to a publican. The family ran an inn near Scole. Educated at Scole Primary School, on finishing his schooling Seaman moved to Trimleyto live with an aunt and work as a page boy in the Grand Hotel in Felixstowe. In 1912, he emigrated to Canada.
On the outbreak of the First World War, Seaman returned to the United Kingdom and tried to enlist in the British Army. He was initially rejected, but he subsequently enlisted at Le Havre. However, he was classified as unfit for active frontline service and was posted to the catering division of the Army Service Corps in late 1915. As the war progressed, the high casualty rates in the British Expeditionary Force saw standards for frontline service lowered and Seaman was transferred to an infantry unit, the 2nd Battalion of The Royal Inniskilling Fusiliers. Serving in the Ypres salient, he was soon awarded the Military Medal for attending, while under fire, to fellow soldiers who had been wounded. The recommendation for his MM was made by his company commander. As part of the 36th Division, Seaman's battalion was engaged in the Fifth Battle of Ypres, a battle of the Hundred Days Offensive, on 29 September 1918. It was tasked with the capture of Terhand. After initial good progress, the battalion was held up by German machine-gun posts. Seaman, a lance corporal operating a Lewis gun, played a key role in getting the advance restarted although he was killed in the process. Afterwards, his bravery was recognised with a posthumous award of the Victoria Cross. The VC, instituted in 1856, was the highest award for valour that could be bestowed on a soldier of the British Empire. The citation for his VC read: Seaman has no known grave but is commemorated at the Tyne Cot Memorial to the Missing near Ypres, the memorial to the 36th Division at the Ulster Tower near Thiepval on the Somme, Felixstowe War Memorial in Suffolk, and the Scole War Memorial in Norfolk. King George V presented Seaman's VC to his mother in a ceremony at Buckingham Palace on 13 February 1919.