Born Ffion Jenkins in Cardiff, she is a native Welsh speaker and first became known when she was selected to teach the language to her future husband when he was Secretary of State for Wales.

She is the younger sister of Manon Antoniazzi, who served as the assistant private secretary to Prince Charles and is now Chief Executive and Clerk of the Senedd.

[2] She attended Ysgol Gyfun Gymraeg Glantaf, a Welsh-language comprehensive school in Cardiff, and went on to study English at Jesus College, Oxford.

William Hague disclosed in September 2010 that she had suffered a number of miscarriages as they tried to start a family.

[10] Hague was appointed a Dame Commander of the Order of the British Empire (DBE) in the 2024 Birthday Honours 'for Public Service and to Business'.