DEARBORN, Mich. — Mark Fields, who helped turn Ford Motor Co.’s North American operations into a sales and profit powerhouse, will take over from Alan Mulally as CEO on July 1, the company announced today.

The 53-year-old Fields has been Ford’s chief operating officer since late 2012, and has been running executive meetings and day-to-day operations. He was widely seen as Mulally’s heir apparent.

Ford wasn’t expected to make the transition until year end, but said it moved up the schedule at Mulally’s request. Mulally, 68, who came to Ford from Boeing in 2006, is credited with transforming the automaker from a dysfunctional money-loser to a thriving company.

Fields takes the CEO job during a transition year at Ford. The company expects pretax profit to fall to between $7 billion and $8 billion from $8.5 billion in 2013, as it launches a record 23 vehicles worldwide and builds seven plants, including four in China. It’s also preparing to launch a new aluminum-clad F-150 pickup truck later this year, which could reap profits down the road but will be expensive to prepare for.