O'Hanlon studied at Trinity College Dublin and the King's Inns.
[1] Her practice primarily consisted of civil litigation and family law matters.
[2] She was a panel member under the Garda Síochána Disciplinary Regulations.
[8] She approved the first ever service of documents via LinkedIn in Ireland in a liquidation case in 2014.
[10][11][12] In January 2022, Simon Coveney appointed her to chair an independent review into issues of sexual misconduct, bullying and harassment in the Defence Forces.