Following the completion of his secondary schooling, he attended University College Dublin, where he became secretary of the Kevin Barry Cumann of Fianna Fáil.

Following Fianna Fáil's re-election at the 1969 general election, Collins secured promotion as a Parliamentary Secretary to George Colley, the Minister for Industry and Commerce and the Gaeltacht.

Four ministers, Charles Haughey, Neil Blaney, Kevin Boland and Mícheál Ó Móráin, were either sacked, resigned or retired from the government, due to the scandal that was about to take place.

Collins, despite coming from a strong republican background, remained loyal to Taoiseach Jack Lynch in his moderate approach to the Northern Ireland situation.

During his tenure as a Minister, Collins introduced a controversial law which prohibited organisations committed to violence, such as the IRA, from making media broadcasts.

Mac Stíofáin was arrested on the same day and the interview was later used as evidence against him on a trial of IRA membership, and on 25 November, he was sentenced to six months imprisonment by the Special Criminal Court in Dublin.

Political fallout arising from the interview was considerable and some days later, Collins sacked the entire RTÉ Authority as he felt that they disobeyed the controversial new law.

In defiance of the opinion polls and political commentators, Fianna Fáil swept to power with a huge 20-seat Dáil majority following the 1977 general election.

He had a good working relationship with the Garda Síochána, primarily due to his establishment of the Ryan tribunal, which saw all ranks receive huge pay increases in his first year in office.

Collins, much to his disappointment, was retained in his existing position as Minister for Justice, holding office until Fianna Fáil lost power following the 1981 general election.

Although Anglo-Irish relations were at an all-time low, Collins opposed the act of aggression by the Argentinian government at United Nations and EEC levels.

Desmond O'Malley was seen as the clear front-runner to succeed Haughey, however, Collins's name was also mentioned alongside former European Commissioner Michael O'Kennedy.

In February 1992, Haughey stepped down as Taoiseach and Fianna Fáil leader and Reynolds immediately threw his hat in the ring in the leadership contest.