She was the eldest child of Richard O'Leary (b. 1866), a Royal Engineer, and Minnie Petheram (b. 1864), natives of London and Gloucestershire, respectively who had married in Swansea in 1891 before going on to have three children, losing one in infancy.
Eileen's only surviving sibling was her younger brother Galbraith (b. 28 January 1899) who was born in Chelsea.
By 1901 Eileen and her family were living in Gillingham, Kent; her parents are recorded on the census residing at 7 Middle Street whilst Eileen is recoded elsewhere as a patient at the Canterbury Road Infections Hospital; the nature of her illness is not stated.
At the time of the 1911 census Eileen and her family were living at 8 Wilton Road, Salisbury, Wiltshire; she was described as an unmarried bookkeeper cashier for Lipton's whilst her father was a clerk in the War Office.
Eileen was married in Corpus Christi Roman Catholic Church in Pokesdown, Bournemouth on 12 January 1912 to Neal McNamee (b. 1884), a provisions dealer for Liptons and a native of Co Donegal, Ireland. The two had met whilst he was working in Salisbury.
Her new husband was offered a position at Lipton Ltd. in America and Sir Thomas Lipton himself wrote a letter of introduction to his General Manager in New York. On hearing that Eileen was leaving for New York, the Superintendent of Salisbury Baptist Church who was also Mayor of Salisbury at the time, Mr W. Pritchard, gave Eileen a letter of kind appreciation and a gift of a testament. This gift was the last item that Eileen's mother saw her pack into her trunk.
The newlyweds boarded the Titanic at Southampton as third class passengers (ticket number 376566, which cost £16, 2s).
It is believed that Lightoller was referring to the McNamees when he recalled events of the evacuation:
... One young couple walked steadily up and down the boat deck throughout pretty well the whole of the proceedings. Once or twice the young chap asked if he could help. He was a tall, clean-bed Britisher, on his honeymoon I should say. The girl--she was little more--never made the slightest attempt to come towards the boats, much less be taken on board, although I looked towards her several times with a look of silent invitation, but no, she was not going to be parted from her man...
Eileen and her husband died in the sinking; her body was recovered by the MacKay Bennett (#53) and buried at sea on 22 April:
NO. 53. - FEMALE. - ESTIMATED AGE, 23. - HAIR, BROWN.
CLOTHING - Brown velvet coat; sailor blouse; white, with blue anchor on front; blue flannel petticoat with "E. M. C."; blue corsets; blue skirt with black braid; black stockings and shoes.
EFFECTS - Wedding ring and keeper (turquois and diamond) gold; bracelet on right wrist; two third class tickets; one purse with 1s. 11d.; fountain pen; keys; cosmetic, & etc.; and cards as below.
NAME - Mrs N. McNAMEE.
A bench with a plaque and a tree were placed in their memory in Winston Churchill Gardens, Salisbury. The original bench is still there but missing the original plaque; the original tree was destroyed by vandals. On 28 July 1999 a new tree was planted and a new bench and plaque unveiled.
What became of her parents in later years is not clear; there is some suggestion that they settled in Canada but there is also a possibility that they spent their final days living in Sidcup, Kent. Her brother Galbraith died in London on 9 August 1979.