The incident happened on the London-bound carriageway near the A2018 just after 7.30am today (April 8).
Officers and South East Coast Ambulance crews attended and found the rider of the motorcycle injured.
He was treated at the scene before being taken to hospital for further treatment where he remains.
Closures were put in place which caused delays of up to 60 minutes and four miles of congestion.
All traffic has since returned back to normal.
A spokesperson for Kent Police said: “Kent Police was called at 7.34am on Tuesday 8 April to a collision involving a car and a motorbike on the London bound carriageway of the A2 Near Dartford.
“Officers and paramedics attended the scene where the motorcyclist was treated for injuries.
“He was taken to a local hospital and the bike was recovered.”
