Constellation Brands Inc., a family-controlled company that transformed itself from a boxed-wine seller to a beverage giant that brews Corona and has bet big on marijuana, is handing the reins to an outsider for the first time.

Rob Sands, the third in his family to lead the Victor, N.Y., company, will step aside as chief executive on March 1, entrusting Constellation’s future—and the success of its beer and cannabis wagers—to one of his lieutenants, Bill Newlands.

During...