He is being treated at Leeds General Infirmary.
The incident happened on the town's 'Golden Mile' of nightclubs and bars at about 4.40pm today.
Police said they were investigating a "pedestrian being knocked down by a car" at the junction of Bradford Road and Hick Lane.
Hick Lane and part of Bradford Road is understood to be cordoned off.
A blue Mercedes, which was involved in the collision, was later recovered by police, the force said.
A spokesperson said: "Enquiries are ongoing to establish the circumstances of the incident.
"Anyone who witnessed the incident or has any further information is asked to contact the police via 101 quoting crime reference number 13190000457 or information can be passed to Crimestoppers anonymously on 0800 555 111."