Thomas Myles was born in Limerick in 1857, the third of eleven children born to John Myles (1807-1871), a wealthy corn merchant, and his second wife Prudence, daughter of William Bradshaw of Kylebeg, Co. Tipperary. The Myles family had been prominent merchants in and around Limerick city since Cromwell's time.
A prominent sportsman from an early age, Myles graduated in medicine at Trinity College Dublin in 1881. One of his duties in his first job as resident surgeon at Dr. Steevens's Hospital was to render medical assistance to the victims of the Phoenix Park murders on 6 May 1882.
By 1900, Myles had become President of the Royal College of Surgeons in Ireland. This was followed by a knighthood and the honorary freedom of his native city.
Myles was also an active Home Ruler. He owned a yacht, the Chotah. In 1914, he was recruited (by James Creed Meredith) to help in the importation of guns for the Irish Volunteers with Robert Erskine Childers, Conor O'Brien and others. Childers landed his part of the consignment from the Asgard at Howth on 26 July 1914. Myles's cargo was landed by the Chotah at Kilcoole, county Wicklow a week later, on the night of 1/2 August. Meredith himself helped out aboard the Chotah during the operation.
Sir Thomas was appointed temporary Lieutenant-Colonel in the Royal Army Medical Corps on 21 November 1914 and also became Honorary Surgeon in Ireland to the King. He was appointed to be an Additional Member of the Military Division of the Third Class, or Companion, of the Most Honourable Order of the Bath, for services rendered in connection with the war, the appointment to date from 1 January 1917.
He died on 14 July 1937 and is buried at Deansgrange Cemetery in Dublin.
- J. Scannell (1995). "The landing of arms and ammunition at Kilcoole, county Wicklow by the Irish National Volunteers in 1914". Greystones Archaeological and Historical Society Journal. 2: 12–18.
- "No One More Nationalist": How Sir Thomas Myles Risked His Position For The Cause, The Irish Press, July 16, 1937