Born near the Bull Ring in Birmingham, she was the youngest of 10 children of parents who left Ireland to escape famine. She is first recorded making screws in Digbeth, and later as a brass polisher in the Birmingham Workhouse Infirmary in Winson Green in 1901. She married Thomas Costello in 1904 and they had 8 children.
Costello was visited twice – in 1951 and 1954 – by folk music researcher Marie Slocombe of the BBC Sound Archive, who recorded 13 songs of hers. Charles Parker visited her in 1967 and recorded a series of interviews. These were combined on a record released in 1975.
The recorded songs of Cecilia Costello largely reflect urban life. She is notable for performing songs from the Irish tradition in a musical and linguistic dialect that identifiably belongs in the English West Midlands, illustrating how immigrant cultures were quickly assimilated within the local musical tradition. A later commentator analysed her work: "To listen to that warm Brummie voice in the excerpts from Charles Parker's interviews ... you wouldn't dream that this old lady was only a generation away from rural Ireland." 
- Palmer, Roy (1972), Songs of the Midlands, Wakefield: EP Publishing, p. v, ISBN 978-0-7158-0377-6
- Costello, Patrick (2003), Cecilia Costello "The Cruel Mother", retrieved 2013-10-06
- Costello, Patrick (2003), Married Life, retrieved 2013-10-06
- "Cecilia Costello", Folk Mag, archived from the original on 2012-05-29, retrieved 2013-10-06
- Costello, Cecilia (1971), "The policeman and The window cleaner", Roy Palmer English Folk Music Collection (London: British Library), retrieved 2013-10-06