Colm O'Gorman will remain as director of the One in Four organisation while seeking to secure one of the five seats in the Wexford constituency for the Progressive Democrats.
Mr O'Gorman said he would not be resigning "at this point" but added that the decision was not just a matter for him, as he was answerable to the board of One in Four.
At a press conference in Dublin this morning, Progressive Democrats party leader and Tánaiste Mary Harney said she hoped Mr O'Gorman's decision would act as a catalyst for others to join the party.
Mrs Harney said she was talking to other "high profile" individuals about joining the party. Asked by RTE's Charlie Bird whether she could name any of the individuals or say how many might join, Mrs Harney laughed, saying: "You might consider it yourself, Charlie?"
Mrs Harney said all small parties faced the challenge of securing candidates and that high profile candidates could command interest from the public.
Mr O'Gorman admitted that he had been approached about entering mainstream politics a number of times since 2002 but declined to name the political parties involved.
"I am no trophy candidate . . . [and] I recognise that politics is viewed as a game, and that many people in this room as in that game", said Mr Mr O'Gorman, before adding that he did not share that view.
He was attracted to the PDs by their passion for reform and said their aim of economic success was not for its own sake but to provide the resources for change.
Mr O'Gorman also said he saw first hand, though his contacts with the Departments of Justice and Health, how the PDs approached Government. He said a series of exploratory conversations eventually led him to decide to join the party.
Asked about the issues exercising constituents in Wexford, O'Gorman said the rapid population growth in the county has seen transport and planning issues come to the fore. He added that he looked forward to hearing about all the other problems over the next 12-months.
Mr O'Gorman has been a high profile campaigner on the issue of clerical sex abuse in recent years.
A native of Wexford, he was abused by the late Fr Sean Fortune who was later revealed as a serial abuser of children in the diocese. The abuse which he highlighted took place in the diocese of Ferns.
The Progressive Democrats have not run a candidate in Wexford since 1989 when they secured just 1.17 per cent of the vote. Fianna Fáil currently holds two seats in the constituency, Fine Gael holds two and Labour one.
