Chrysler Group LLC said on Monday that U.S. sales chief Reid Bigland will head Alfa Romeo in North America, a move that comes as parent Fiat SpA seeks to cement the luxury brand’s return to the U.S. after a nearly two-decade hiatus.

Mr. Bigland, who will remain head of U.S. sales and chief executive officer for Chrysler Canada, took over the Ram brand in 2013 and oversaw a sharp rise in its U.S. pickup truck sales. The company said…