Seamus Mallon was born in the largely Protestant village of Markethill to Jane (née O'Flaherty) and Francis Mallon, and was educated at the Abbey Christian Brothers Grammar School in Newry and St Patrick's Grammar School, Armagh.

As a career he (like his father) chose teaching, and became headmaster of St James's Primary School in Markethill.

Between May and December 1982 he was appointed by the then Taoiseach Charles Haughey to the Republic's upper house, Seanad Éireann.

There is a fundamental question to be asked outside of the legalities of the emergency provisions legislation, of the statistics and of the emotions that it engenders.

Is it not even more fundamental to ask why, after 72 years, all those measures have never brought peace, stability or unity of purpose to the north of Ireland?

[13] He has frequently been quoted as saying that the Good Friday Agreement, which resulted from the talks in 1998, was "Sunningdale for slow learners".

[14][15][16] The Good Friday Agreement led to the setting up of the Northern Ireland Assembly, which was elected in June 1998, with a power-sharing Executive.

Mallon was elected as member for Newry and Armagh, and in December 1999 became Deputy First Minister of Northern Ireland, serving alongside Ulster Unionist Party leader David Trimble.

[17] Mallon remained a strong opponent of IRA violence,[10] and was also in favour of police reform in Northern Ireland.

[19] Mark Durkan replaced both, Hume as leader and Mallon as Deputy First Minister, when the Northern Ireland Executive was re-established following a suspension.