Sir Philip Barton has been appointed a senior official in the new Foreign, Commonwealth and Development Office.
The UK High Commissioner in New Delhi will take office as Permanent Secretary on September 1.
He replaces Sir Simon McDonald, who was asked in June to step down before the merger “at the request” of the Prime Minister.
Foreign Minister Dominic Raab welcomed Sir Philip to the department, calling him an “exceptional civil servant”.
Boris Johnson announced in June that he plans to merge the Department for International Development (DfID) – which is responsible for overseas aid – with the Foreign and Commonwealth Office by September.
He told MPs that the “long overdue reform” would provide “maximum value” to taxpayers.
The PM was supposed to want someone new in charge of the department, so asked Sir Simon to step down after five years in the role.
Sir Simon said he “fully” respected the decision and that the merger was “the right decision for our future overseas efforts”.
But he was one of four senior officials to announce their departure from Whitehall in six months amid reports of mounting tensions with key members of Team No.10.
Sir Philip has held a number of public service positions, including as Director General, Consular and Security at the Foreign Office and Acting Chairman of the Joint Intelligence Committee at the Cabinet Office.
He was also a former high commissioner in Islamabad, deputy head of mission in Washington, director of foreign policy and coordinator for Afghanistan and Pakistan.
Sir Philip Barton has a tough job on his hands as the first permanent secretary of a new Whitehall department – the result of an uncomfortable congress between the Foreign Office and the International Development Department.
He will have to assemble two different organizations with two distinct cultures and two distinct objectives. This will require skillful bureaucratic work.
Sir Philip is also assuming this role just as the government is conducting a so-called ‘integrated review’ of UK foreign policy which his department will be asked to carry out.
On paper, Sir Philip has the skills to answer all of this – an old man in life in the Foreign Office who has been posted all over the world.
He has no direct experience working for DFID, but he was formerly High Commissioner to Pakistan, which is the largest recipient of British foreign aid.
Sir Philip has served his time as a warrior in Whitehall, as acting chairman of the Joint Intelligence Committee and as private secretary in Downing Street for Sir John Major and Tony Blair.
Strangely enough, little of his career involved Europe.
Sources from Whitehall say Sir Philip is respected as a diplomat and civil servant, and is highly regarded, which will be crucial when he tries to link FCO and DFID staff.
Others note that his appointment is orthodox and conservative; a safe pair of hands for a tricky government reorganization.
Sir Philip said he was’ delighted ‘to have been appointed, adding:’ I look forward to bringing together our diplomats and development experts to serve the people of the UK and act as a force for good in the world. ”
Mr Raab added: “Philip is well positioned to bring together the talents and expertise of the two departments while helping to combine our foreign and development policy in an innovative, ambitious and more integrated way than ever. “