Gareth Rogers has been announced as the interim CEO at Saints.
Rogers was previously the chief financial officer under former executive chairman Nicola Cortese and has worked at the club since March 2011.
His appointment is seen as a mark of faith in the existing staff at St Mary's under the new regime.
There is no exact timescale on how long the interim appointment is for, but it is believed Rogers will be in charge at least until the summer.
As reported previously by the Daily Echo, a board of non-executive directors will also be appointed, though that is not expected to happen until Ralph Krueger has seen through his commitments with the Canadian ice hockey team at the upcoming Winter Olympics.
In a statement club owner and Saints non-executive chairman Katharina Liebherr said: "I am delighted that Gareth has agreed to step into this role. After the events of the past week, my priority has been to bring stability to the management of the Club and I am pleased that we have been able to make this appointment from within.
"We had a very positive meeting with all the staff of the Club on Monday and I am sure Gareth's appointment will be warmly received.”
Rogers graduated from the University of Southampton with a BSc in Economics and Accounting and worked at Deloitte's before taking up his role at Saints.
He said: "I am very pleased to be able help the club by stepping up to the CEO’s job on an interim basis. We have a fantastic staff and everyone is working together to make sure the club ends the season as strongly as possible.”