The attacker, who was on a motorcycle, detonated his explosive vest when the convoy of Frontier Constabulary commandant Abdul Majeed Khan Marwat slowed down near a check post in Sadar area within Peshawar cantonment.
Marwat remained safe though his vehicle was damaged.
Two women were killed instantly while four men succumbed to their injuries in hospital, officials said.
The injured were taken to the Lady Reading Hospital and a military hospital. Officials said four Frontier Constabulary personnel were among the injured. Some of the wounded were in a serious condition, they said.
Marwat told the media that his convoy was the target of the attack. He said the explosion occurred a short distance from his vehicle.
Other officials said the bomber's suicide vest contained an estimated 10 kg of explosives. The bomber struck Marwat's convoy at a short distance from the US Consulate.
Footage on television showed several vehicles and motorcycles were damaged by the explosion.
Ambulances rushed the injured to hospital as paramilitary personnel and army soldiers cordoned off the area. Witnesses said they had seen the body parts and the head of the bomber.
No group claimed responsibility for the blast though such attacks are usually blamed on the banned Tehrik-e-Taliban Pakistan.
In August 2010, then Frontier Constabulary commandant Sifwat Ghayur was killed in a similar suicide attack on his convoy in the same area of Peshawar.