He was educated initially at Elm Park preparatory school, Killylea, County Armagh, but at 14 was sent to the Church of Ireland-affiliated St Columba's College at Rathfarnham in Dublin, although Faulkner was Presbyterian.

In 1956 Faulkner was offered and accepted the job of Parliamentary Secretary to the Ministry of Finance, or Government Chief Whip.

In 1959, he became Minister of Home Affairs and his handling of security for most of the Irish Republican Army's Border Campaign of 1956–62 bolstered his reputation in the eyes of the right wing of Ulster unionism.

In the ensuing leadership contest, Faulkner lost out again when O'Neill gave his casting vote to his cousin, James Chichester-Clark.

Faulkner came back into government as Minister of Development under Chichester-Clark and in a sharp turn-around, began the implementation of the political reforms that were the main cause of his resignation from O'Neill's cabinet.

In his initial innovative approach to government, he gave a non-unionist, David Bleakley, a former Northern Ireland Labour Party MP, a position in his cabinet as Minister for Community Relations.

The shooting of two Catholic youths in Derry by British soldiers prompted the SDLP, the largest Nationalist party and main opposition to boycott the Stormont parliament.

The political climate deteriorated further when, in response to the worsening security situation, and in a move without precedent in the United Kingdom in modern times, Faulkner introduced internment on 9 August 1971.

David Bleakley resigned in September 1971 over internment and Faulkner appointed Dr G. B. Newe, a prominent Catholic, as Minister of State in the Cabinet Office.

In January 1972, an incident occurred during a Northern Ireland Civil Rights Association march in Derry, during which paratroopers shot and killed thirteen unarmed civilians.

The Stormont parliament was subsequently prorogued (initially for a period of one year) and following the appointment of a Secretary of State for Northern Ireland, William Whitelaw, direct rule was introduced.

However, the prominence in the Sunningdale Agreement of the cross-border Council of Ireland suggested that Faulkner had strayed too far ahead of his party.

She was equally suited to a political partnership having had a career in journalism with the Belfast Telegraph and was secretary to the Northern Ireland Prime Minister, Sir Basil Brooke, when they met.

One of his sons, Michael, has written a memoir, The Blue Cabin (2006) about his move to the family's former holiday house on the island of Islandmore on Strangford Lough.