Martin appointed Ó Cuív as Deputy leader of Fianna Fáil, following Brian Lenihan Jnr's death.

However, Ó Cuív ceased to be Deputy leader of Fianna Fáil on 29 February 2012, because of his opposition to his party's stance on the European Fiscal Compact.

Ó Cuiv is the grandson of Fianna Fáil founder, Taoiseach and President of Ireland, Éamon de Valera.

Ó Cuív is the son of Brian Ó Cuív, professor of Celtic Studies at University College Dublin, and Emer de Valera, who was the last surviving daughter of Fianna Fáil founder, Taoiseach and President of Ireland Éamon de Valera, when she died at the age of 93 in February 2012.

[3] Before entering politics, he was the manager of Gaeltacht Co-operative, a company involved in agricultural services including timber milling, tourism and cultural development.

His vote had increased significantly and he was elected on the first count, coming a close second for Fianna Fáil behind the Labour Party's Michael D. Higgins.

[7] In 1994, Ó Cuív raised concern amongst some in Fianna Fáil when he suggested the possibility of a prospective conditional return to the Commonwealth of Nations as a gesture to Unionists in Northern Ireland.

Ó Cuív was at the centre of a controversy surrounding the official name of An Daingean / Dingle, a small Gaeltacht town in west County Kerry.

Ó Cuív originally signalled that he was happy to abide by the locals' decision,[citation needed] but then said that the name could not legally be changed back to Dingle, following advice from the Attorney General of Ireland.

[23] On 12 July 2012, Ó Cuív was reappointed to the Fianna Fáil front bench as Spokesperson for Agriculture and Food, and on Community Affairs.

On 8 November 2018, Ó Cuív was sacked from the Fianna Fáil front bench for unveiling a candidate in a Northern Ireland election without the party's permission.