The leader of the Corrymeela Centre has died aged 62 after a short battle with cancer.
David Stevens was known for his commitment to peace and reconciliation and was a former head of a group involving Irish churches.
He helped attract European money aimed at cementing the peace process and was a founding member of the Community Relations Council (CRC).
CRC chief executive Duncan Morrow said: "He never became institutionalised. He was a person willing to say the unpopular things if only for what he thought were good purposes."
He said he was willing to tell the truth when others were pulling their punches.
Mr Morrow added: "He was never a softly, softly community relation worker, he was very much 'this matters because these are the alternatives...'"
Mr Stevens, from Holywood, Co Down, was leader of the Corrymeela Centre from 2004 and was a member of the CRC for many years.
He carried out research on faith and politics in the 1990s when the armed conflict was continuing.
He helped bring peace funding from the European Union to boost grassroots development and the peace process.
Mr Morrow added: "In some ways the theme of reconciliation has become the predominant theme of our times."