The US special envoy to the North, Mitchell Reiss, is to step down later this month after almost three years in the post.
He will be replaced by Paula Dobriansky (51), a prominent neo-conservative intellectual who is currently undersecretary of state for democracy and global affairs.
Dr Reiss told The Irish Times that he was grateful to secretary of state Condoleezza Rice for retaining him as special envoy after he left the state department two years ago.
"I think that we've used that time very productively to move the peace process forward. And she's decided that now would be a good time to make a transition and to bring the job back into the state department," he said.
Dr Reiss said he was delighted that Dr Dobriansky, whom he has known for almost 30 years, has agreed to succeed him.
"Paula and I have already had extensive conversations about the nature of the job and the American role.
"Specifically, I told her how much progress has been made in the peace process over the past few years and that she's entering it now at a very propitious moment.
"She and I will be travelling to Northern Ireland at the end of this month and I'll be introducing her to all our colleagues and counterparts, and making sure that the transition is as seamless as possible."
Dr Dobriansky was a founding member of the Project for the New American Century, a neo-conservative think-tank, and signed a letter in 1998 calling on then president Bill Clinton to remove Saddam Hussein from power, by force if necessary.
"Although we are fully aware of the dangers and difficulties in implementing this policy, we believe the dangers of failing to do so are far greater.
"We believe the US has the authority under existing UN resolutions to take the necessary steps, including military steps, to protect our vital interests in the Gulf. In any case, American policy cannot continue to be crippled by a misguided insistence on unanimity in the UN Security Council," the letter stated.
A vociferous advocate of US president George Bush's stated policy of promoting democracy in the Middle East, Dr Dobriansky is responsible for a broad range of foreign policy issues at the state department, including democracy, human rights, labour, refugee and humanitarian relief matters, and environmental/science issues.
Dr Reiss said the US role in the Northern peace process was constantly evolving, depending on circumstances on the ground.
"I think we've maintained a very strong record of constant commitment to this issue and I think that it has continued, along with the work of many other people, to where we are today, which is a remarkable place.
"It's very different to where we were just a few short years ago," he said, adding that he will cherish the friendships he made while special envoy.
"The great joy in this job has been meeting the magnificent people in Ireland, both North and South and in Irish-America. It has been a remarkable personal and professional experience and one that I will always cherish," he said.