Walgreens' Stefano Pessina will step down as CEO and become executive chairman once the drugstore chain finds a replacement for him.
The current executive chairman, former McDonald's CEO Jim Skinner, will remain on the board after Pessina takes over.
The company announced no time frame Monday in finding a successor to Pessina.
The change in leadership comes a couple weeks after Walgreens announced a huge quarterly loss and a major business pivot.
Walgreens posted a quarterly loss of $1.7 billion with millions of people sheltering at home. The chain also announced that it will squeeze primary care clinics into as many as 700 of its U.S. stores over the next few years in a major expansion of the care it offers customers.
Walgreens Boots Alliance, based in Deerfield, Illinois, runs more than 9,200 stores in the United States and has more than 18,750 locations internationally.
Company shares slipped at the start of trading Monday.