Dalton Philips is leaving Morrisons next Monday, leaving Trevor Strain to take on the role on an interim basis.
The ailing supermarket revealed Philips was leaving last month, prompting Morrison's share price to rise. Although it said the search for a replacement was “progressing well”, he is stepping down well before anyone is in place to pick up the reins.
Morrisons said it was “the appropriate time for Dalton to relinquish his responsibilities” as the supermarket's financial year ended on February 1.
Strain will chair the board and take on Dalton's executive responsibilities until a replacement is found.
Chairman Andrew Higginson will also spend more time in the business until the new chief executive is in place.
He said: "We're making good progress with the search for a new chief executive.
“With Trevor Strain chairing the management board, together with the retailing strength and depth that I've seen in my short time at Morrisons, I'm confident that it will be business as usual during this transitional period."
Morrisons' share price was up 0.7 per cent at pixel time.