As former director of the UN's oil-for-food programme, Benon Sevan is now caught up in the scandal surrounding the programme for Iraq.
Benon Sevan headed the oil-for-food programme from 1997
He has been accused of taking nearly $150,000 in cash bribes by a panel investigating corruption allegations.
The 67-year-old's resignation on Sunday ahead of the expected accusations brings to an end four decades of service with the UN.
Posted to some of the world's major hotspots, Mr Sevan, who was born in Nicosia and is of Armenian ancestry, has had a string of key positions.
In 1988, he was sent to Afghanistan and Pakistan as a special adviser, monitoring the Soviet withdrawal from Afghanistan after nearly a decade of conflict.
The following year, he was promoted to assistant secretary general and the secretary general's personal envoy to the region, later heading the humanitarian effort there.
He had also worked extensively in the Middle East, before being appointed head of the oil-for-food programme in 1997.
In 1985, he was sent on special mission to examine the fate of prisoners on both sides in the Iran-Iraq war.
And from 1992, as well as his other duties, Mr Sevan served as the special envoy for missing persons in the Middle East.
His first senior posting to a trouble spot came soon after he joined the UN Secretariat in 1965.
Mr Sevan was caught up in the UN HQ bombing in Baghdad
From the end of 1968 to the summer of 1969, he served as an observer of the controversial final stage of the decolonisation of West Irian (now Irian Jaya) and its incorporation into Indonesia.
He subsequently worked for two years on the UN development fund for the region.
And Mr Sevan's work as the oil-for-food boss also brought danger, with the official halfway through a televised news conference at the UN headquarters in Baghdad on 19 August 2003 when a truck bomb devastated the building, killing 22 people.
The UN special envoy to Iraq, Sergio Vieira de Mello, was among the dead.
Mr Sevan, speaking at a ceremony in Baghdad as Mr Mello's body was about to be flown out, quoted a US soldier who said the envoy, dying under the rubble, had told him: "Don't let them pull the mission out."
The oil-for-food programme was wound up at the end of 2003, and Mr Sevan retired in May 2004.
By that time, he had agreed to continue on the UN payroll on a salary of $1 a year and co-operate with the investigation into corruption in the programme.
In February, an interim report by Paul Volcker's panel into the scandal said Mr Sevan had tried to allocate oil sales from Iraq.
Payments of $160,000, which Mr Sevan said came from his aunt in Cyprus, have been questioned. The bureaucrat has said the notion he would risk his career over such a sum when he was administering billions is incredible.
The August report by the panel has recommended that UN Secretary General Kofi Annan lift Mr Sevan's UN immunity for the "purposes of a criminal investigation".
His resignation ends 40 years of a plethora of roles within the UN, which also included appointments in the 1990s as deputy head of the Department of Political Affairs, and assistant secretary general in the Department of Administration and Management, in charge of the restructuring of the UN.
Mr Sevan was educated at the Melkonian Institute in Cyprus, and then studied history and philosophy at Columbia University in New York, eventually doing a post-graduate degree at the school of international and public affairs there.
He is married and has a daughter.