On his return next month, Wintersgill takes over as managing director for Scotland & North East as well as being given senior responsibility for the Northern and North West regions.
He replaces Brian McQuade, who left Kier to join Robertson at the end of October.
The move is part of a fresh shake-up among the regional divisions as the debt-laden group battles to reduce costs and drive efficiencies.
The Thames Valley division is being disbanded with Southern and Thames Valley director Jonathan Payne exiting.
Other regional directors are getting extra responsibilities in the regional operational restructure.
In a statement, Kier said: “Across all of our businesses we need to continue to drive efficiencies and ensure that we are as cost-effective as possible.
“There have been some significant changes across our regional building teams to achieve this and we need to continue to simplify the Group, to improve cash generation, and reduce net debt through divestments and cost reduction.
“To support this, we have rationalised the regional building model in our Southern and Thames Valley regions.”
The Southern division’s Aylesford office, which continues to be led by operations director, Matthew Parsler, is now part of an extended London and South East region reporting to managing director, Cliff Thomas.
Another Southern division office in Reading, led by operations director, Glyn Salmon, now joins the Central region, under managing director Mark Pausey.
Former Thames Valley division offices in Maple Cross, Solent, Crawley and Guildford are now aligned as one enlarged Southern business.
Western & Wales division managing director Anthony Irving will widen his responsibility to also provide leadership over the enlarged Southern region.