In a moving tribute, Attorney General Rory Brady SC praised his former colleague for his vast contributions to political and legal life in Ireland.
“No barrister that I know can claim as much influence on the political system as Eamon,” said Mr Brady.
One of the greatest tributes paid to Mr Leahy was how many countries had copied ground-breaking Irish legislation relating to the seizure of criminal assets, of which the late barrister had been the architect, said Mr Brady.
Mr Leahy, 46, who was also a Fianna Fáil strategist, died suddenly last Thursday in Donegal, where he was legal representative of the Garda Commissioner at the Morris Tribunal.
Chief mourners at the funeral mass at the Church of St John the Baptist in Blackrock, Co Dublin, were his wife, the Government chief whip Mary Hanafin, his father Eamon, and brothers Fergal and Tom.
Also present were Ms Hanafin’s father, the former Fianna Fáil senator Des Hanafin, and his wife Mona, as well as her brothers Tom and John, who did the readings.
Official dignitaries were led by the President Mary McAleese; Taoiseach Bertie Ahern; Tánaiste Mary Harney and other members of the Cabinet, including Mr Leahy’s close friend, the Minister for Arts, Sport and Tourism John O’Donoghue, as well as many Fianna Fáil TDs, senators, MEPs and councillors.
Also in attendance were the Chief Justice Ronan Keane; Garda Commissioner Noel Conroy; and Major General James Sreenan of the Defence Forces, as well as many of Mr Leahy’s colleagues from the Bar Council, and members of the judiciary including Feargus Flood, Michael Moriarty and Frederick Morris.
Other politicians attending the service were Labour leader Pat Rabbitte; Fine Gael chief whip Bernard Durkan; Sinn Féin MP Martin McGuinness; and Green Party TD John Gormley.
Music for the liturgical mass was provided by the Vard sisters.
The service was concelebrated by more than 20 priests, led by Fr Martin Clarke, a family friend and director of the Catholic Communications Centre in Maynooth. Also present were the Auxiliary Bishop of Dublin Dr Eamon Walsh and the Bishop of Cloyne Dr John Magee, who married Mr Leahy and Ms Hanafin in 1985.
Among the gifts presented during the offertory were a recent holiday photo of the couple, Mr Leahy’s wig and a copy of the Irish Law Report.
In his homily, Fr Clarke praised Mr Leahy for the major contributions he had made to public and professional life through his various roles with numerous bodies and organisations, including the Legal Aid Board.
He described the late barrister as a “larger than life” character and “a gentle giant” who was known widely for his even-handedness, joie de vivre and hospitality.
Mr Leahy was buried at Fingal Cemetery in Balgriffin.