The Dublin-born actress grew up by the sea in Sandycove and is the voice actor for Caitlin in the children's television series Thomas & Friends.
O'Mara attended Holy Child Killiney before completing a degree in Drama and Theatre at Trinity College Dublin.
[2] She has also worked extensively in theatre in the UK and Ireland since graduating from the London Academy of Music and Dramatic Art (LAMDA).
[3] She played Minnie Larkins in The History of Mr Polly, Mrs. O Keefe in the 2014 Ken Loach film Jimmy's Hall and has guest starred in various television programmes including Line of Duty and Doctors, but is probably best known for her role as scene of crime officer, Frankie Hynes, in TV3's Red Rock.
In March 2019, she won the Irish Times Theatre Award for Best Actress in a Supporting Role for the performance.