Melloney has been a charity and public administrative law lawyer since 2003, following 25 years of high value and complex private sector commercial and corporate experience. She developed the Legal Department which supported all the legal and governance matters for the Arts Council England, Heritage Lottery Fund and Big Lottery Fund and was awarded an OBE for legal and governance services in 2011.

In 2015, Melloney set up and ran the new Armed Forces Covenant Fund which is now an independent charitable trust and NDPB.

Melloney has had a parallel Non-Executive career as a director and chair in the NHS serving on the boards of four NHS Trusts and their charities and the Chair of both Portsmouth Hospitals University Trust and the Isle of Wight NHS Trust. She has been the chair of Governors, vice-chair of the Regional Committee of the National Lottery Charities Board and of The Health Foundation, Meals on Wheels volunteer, fundraiser, parish councilor, magistrate on the Preston bench for two years and volunteers for cancer related and community charities.