Carolyn Holt, praised for her “rich and seductive mezzo-soprano” (Bachtrack), is from a farming background in Ireland. She has covered and performed with the Royal Opera House, English National Opera, Garsington Opera, Scottish Opera, Welsh National Opera, and Irish National Opera. Recent engagements for the Royal Opera House, Covent Garden, include the role of Bianca (The Rape of Lucretia) at the Linbury Studio, and the covers of Mrs Sedley (Peter Grimes) and Margret (Wozzeck). Elsewhere in the UK, recent engagements include Mrs Grose (The Turn of the Screw) for Garsington Opera, Madame Larina (Eugene Onegin) as an 'Opera First' Garsington Alvarez Young Artist, Sister Helen Prejean (Dead Man Walking – UK staged premiere and cover with Welsh National Opera), Mary (The Flying Dutchman) with OperaUpClose, Dido (Dido and Aeneas) and Prince Orlofsky (Die Fledermaus). Recent performances in Ireland include Minskwoman (Flight) with Opera Collective Ireland, Charlotte (Werther) and Gertrud (Hansel and Gretel) with Lyric Opera Productions at the National Concert Hall, and Annina (Der Rosenkavalier) with Irish National Opera. 

She was the winner of the Dermot Troy Prize for the best Irish singer in the 2019 Veronica Dunne International Singing Competition and was awarded the top prize in their inaugural bursary in 2020. She has been a semi-finalist in many international competitions including the Virgilijus Noreika Competition and the Elizabeth Connell Prize, both in 2023.

In concert, Carolyn has sung Mahler's Lieder eines fahrenden Gesellen with the Esker Festival Orchestra, Elgar’s Sea Pictures with Lambeth Orchestra, The Angel in Elgar’s Dream of Gerontius, and Messiah at the Waterfront Hall, Belfast. She is invited regularly as soloist with orchestras and choral societies throughout the UK and Ireland where critics acclaim her “wonderfully dark, rich tone”.