The national newspaper division of GMG is considering both external and internal candidates and is expected to name the managing director by early July. Stuart Taylor, the newspaper's commercial director, is being widely tipped for the role.
McCall, a former ad director and deputy managing director of Guardian Newspapers, will replace Sir Robert Phillis as the chief executive of GMG on 1 August.
Phillis will continue as a non-executive director on the GMG board. McCall has also been invited to join the Scott Trust, the ten-strong body that runs and owns GMG.
Paul Myners, the chairman of GMG, said: "Carolyn has a very clear and compelling vision for the growth and strategy of the group."
McCall said: "GMG is well placed to take advantage of all the opportunities being created by the enormous changes in the media market."