It emerged on Monday night the 47-year-old actor was a passenger in the car when the crash occurred at around am on Thursday, according to CBC News.
The vehicle, driven by a 59-year-old man whose name has not been released, was hit by the police car.
The Royal Newfoundland Constabulary said: "As a precaution, one of our officers was also transported to hospital."
Officials added Hartnett, his driver and the officer were all assessed for minor injuries by medical staff. Both vehicles were said to have been "significantly damaged" in the collision.
Investigators have appealed for witnesses and for anyone with video of the incident to come forward.
Hartnett had been returning from work on a Netflix production that has yet to be formally titled.
The project – referred to locally as the "untitled Netflix Newfoundland series" – features a cast including Mackenzie Davis, Darrin Baker, Charlie Heaton, Tanchay Redvers, Joshua Close, Rohan Campbell, Ruby Stokes, Kaleb Horn, Willow Kean and Natasha Henstridge.
Born in Saint Paul, Minnesota, Hartnett first rose to prominence in the late 1990s, appearing in films such as Halloween H20: 20 Years Later and The Faculty.
His breakthrough role came in 2001 with Pearl Harbor, followed by leading parts in Black Hawk Down and the thriller Lucky Number Slevin.
By his mid-20s, he was considered one of Hollywood's leading young actors, frequently appearing on magazine covers and in studio blockbusters.
Hartnett later stepped back from the spotlight, focusing on independent cinema and television roles.
His more recent credits include appearances in Penny Dreadful, Guy Ritchie's Wrath of Man and Christopher Nolan's Oppenheimer.
The Netflix project currently shooting in Newfoundland marks another high-profile return to screen work.
Police said inquiries into the crash are ongoing.
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