She served as the Member of Parliament for the constituency of North Down between 2001 and 2019.
She was first elected for the Ulster Unionist Party but since 2010 sat as an Independent unionist.
She is the widow of Sir Jack Hermon, who served as Chief Constable of the Royal Ulster Constabulary.
She was the only independent MP elected at the 2017 General Election.
On 25 March 2010, Lady Hermon announced her resignation from the Ulster Unionist Party, and has served since then as an Independent MP.
Her decision was triggered by the Ulster Unionist alliance with the Conservative Party.
She successfully retained her seat in the May 2010 election with a large gain in her share of the vote, increasing her majority, retaining the seat again in the May 2015 election.
She also retained her seat in 2017 with a reduced 41% of the vote.
She announced her decision not to contest her seat at the December 2019 general election in November 2019.