Doyle entered St Leo's Convent of Mercy, Carlow on 30 April 1849, where she taught at the adjoining school for 5 years.
[2] Doyle was one of a number of Sisters of Mercy nuns who volunteered at the outbreak of the Crimean War to serve as nurses at the front.
Doyle and her fellow nuns were the subject of intense scrutiny and despite their denials, the war office warned them not to proselytise.
During Queen Victoria's diamond jubilee, Doyle was awarded the Royal Red Cross in 1897 as the only surviving Irish war-nurse.
When asked to recall her memories of Florence Nightingale, she said she didn't like her and found her "too bossy" but "that she was a great woman for getting things done".