Police, ambulance service and fire crews were all called to the incident, which was said to have taken place on Dalton Piercy Road, on the outskirts of Dalton Piercy, at around 7.10pm on Sunday.
The incident involved a black Audi A3 and Cleveland Fire Brigade said that the vehicle had rolled over.
Fire crews spent over five hours at the scene, leaving at around 12.33am on Monday.
Two men were injured and were taken to James Cook Hospital, in Middlesbrough.
Cleveland Police have said the driver remains in critical condition.
A police statement said: “At around 7.10pm on Sunday night police were contacted by fire brigade colleagues reporting a single vehicle collision on Butts Lane outside Dalton Piercy.
"It involved a black Audi A3 and two men in their 30s sustained injuries in the incident.
"Both were taken by ambulance to hospital. The driver remains in a critical condition and the passenger self-discharged with apparently minor injuries.
“The road was temporarily closed to allow vehicle recovery to take place and collision enquiries to get underway. The investigation is ongoing.”
Cleveland Fire Brigade added: “We were called out at 7.07pm on 17 July to a road traffic accident near Grove House, Butts Lane, Dalton Piercy, which involved a vehicle that had rolled over.
"Two appliances attended, one from Hartlepool Community Fire Station and one from Stockton Community Fire Station. Two casualties were taken to hospital.”
The North East Ambulance Service dispatched two double crewed ambulances and requested support from a Great North Air Ambulance doctor.