Construction director Steve Bowcott is being promoted to the new expanded group job of chief operating officer.
In the new role he takes responsibility for the operational efficiency of both the construction and the services divisions within the enlarged group.
Following shareholder approval, Kier will complete its £221m takeover of May Gurney on 8 July.
The group finance director, Haydn Mursell, will assume operational responsibility for the property division, in addition to his current responsibilities.
As a result of these changes, Ian Lawson has today retired as a director from the board.
Phil White, chairman of Kier, said: “The introduction of the COO role, together with clearly defined roles and responsibilities for each of the executive directors and an experienced senior management team, will enable the business to continue to deliver a strong trading performance which will, in turn, provide a sound platform for future growth.”