(James) Emmet Dalton was born on March 4, 1898 in Fall River, Massachusetts, to Irish-American parents James Francis and Katharine Lee (Riley) Dalton. The family moved back to Ireland when he was two, and he was raised Catholic in North Dublin. In 1913, Dalton joined the nationalist militia, the Irish Volunteers, and then joined the British Army in 1915 for the duration of World War I.

Dalton joined the 7th Battalion of the Royal Dublin Fusiliers (RDF) as a 2nd Lieutenant. By 1916, he was attached to the 9th Battalion, RDF, 16th Division under Major-General William Hickie, which contained many Irish nationalist recruits. In September 1916, Dalton fought during the Battle of Ginchy, in which over 4,000 Irishmen were killed or wounded. Dalton was awarded the Military Cross for his conduct in the battle. Later he was transferred and sent to Greece, then Palestine, where he commanded a company and supervised a sniper school. In 1918, Dalton was redeployed again to France and promoted to captain.

On demobilization in April 1919, Dalton returned to Ireland. Dalton followed his younger brother Charles F. Dalton in joining the Irish Republican Army (IRA). He quickly became close to Michael Collins, who at the time was Director of Intelligence for the IRA. Dalton succeeded Collins as the IRA Director of Intelligence, and became involved in the Squad, the Dublin-based assassination unit. Dalton accepted the Anglo-Irish Treaty in 1922 and was one of the first officers, a Major General, in the new National Army established by the Irish Provisional Government of the Irish Free State. He was in command of troops in the Battle of Dublin which marked the start of the Irish Civil War in June 1922, and became commander of the Free State Army under Richard Mulcahy's direction.

Dalton married Alice Shannon on October 9, 1922 in Cork's Imperial Hotel. They had five children, including actress Audrey Dalton. By December 1922, Dalton had resigned his command in the Army after the death of Michael Collins. He did not agree with the treatment of republican prisoners that marked the later stages of the Irish Civil War. After briefly working as clerk of the Irish Senate, he left this job to work in the movie industry. Over the next forty years, he worked in Ireland and the United States in film production. In 1958, he founded Irish Ardmore Studios. His company produced many films, all of which were filmed in Ireland. Emmet Dalton died in Dublin in 1978 on March 4, his 80th birthday.

Sources:

Dempsey, Pauric J., Shaun Boylan. "Dalton, (James) Emmet." Dictionary of Irish Biography. October 2009, https://www.dib.ie/biography/dalton-james-emmet-a2369

Harrison, Shane. "Emmet Dalton: From Michael Collins' right hand man to movie producer." BBC. August 22, 2022, https://www.bbc.com/news/world-europe-62549024