Background
O'Neill was the second but eldest surviving son of Edward O'Neill, 2nd Baron O'Neill, and his wife Lady Louisa Katherine Emma (née Cochrane).
politician Member of Parliament in the United Kingdom
O'Neill was the second but eldest surviving son of Edward O'Neill, 2nd Baron O'Neill, and his wife Lady Louisa Katherine Emma (née Cochrane).
Eton.
Military career
O'Neill joined the British Army in 1897. He saw active service in South Africa between 1899 and 1900, during the Second Boer War. In January 1902, he was temporary appointed Adjutant to the 2nd Regiment of Life Guards.
O'Neill fought in the First World War as a Captain in the 2nd Life Guards and was killed in action at Klein Zillebeke ridge, 6 November 1914, aged 38, the first MP to be killed in the conflict. Political career.
Unionist.
29th United Kingdom Parliament. 30th United Kingdom Parliament.
Spouse 1902, Lady Annabel Crewe-Milnes, daughter of 1st Earl of Crewe.