The Hingham store was seen with a large hole in its glass front and first responders were present just prior to 11:00 a.m., less than an hour after the store opened at 10:00 a.m.
Investigating officers didn't specify whether the crash was believed to be accidental as of Monday.
Plymouth County District Attorney Tim Cruz said 14 victims were transported to South Shore Hospital and Weymouth, while two others were taken to hospitals located in Boston.
Four of the 16 victims were reported to be in critical condition as of Monday.
"This morning was an unthinkable morning, and people are trying to get through it and process what happened. It appears at the outset, preliminarily, the dark-colored SUV, went through at a rate of speed undetermined, through a plate glass window and struck multiple people. This investigation is active and ongoing," Cruz said via WBZ.
Cruz said the driver was "with police officers" and investigators were determining whether the driver was treated for any medical issues.
A bystander at the scene told WBZ's Jim MacKay that the vehicle was estimated to be traveling between 50 and 60 MPH and accelerated before crashing into the storefront.
The Apple Store is located at Derby Street Shops, which primarily has an open space area for shoppers.