The attacker targeted Sherpao's motorcade as he was travelling to Peshawar after addressing a rally in Charsadda district of Khyber-Pakhtunkhwa province.
The bomber detonated his explosive vest as the convoy was moving along a narrow street in a village.
Sherpao, Interior Minister during former military ruler Pervez Musharraf's regime, escaped unhurt while his son Sikander, the driver of their car and legislator Mohammad Ali sustained minor injuries, officials said.
District police chief Nisar Khan Marwat said a constable was killed and three policemen were among the injured.
The Tehrik-e-Taliban Pakistan claimed responsibility for the attack.
A spokesman for the Taliban in Mohmand tribal region called journalists in Peshawar and said his group had carried out the attack.
The injured were taken to Lady Reading Hospital in Peshawar, the capital of Khyber-Pakhtunkhwa.
Footage on television showed Sherpao and his son leaving the hospital along with their supporters.
Sherpao's SUV was damaged by ball bearings packed into the suicide bomber's vest.
Shards of glass lay on the seats, which were spattered with blood.
Officials said a police vehicle had borne the brunt of the blast.
Sherpao heads the Pakistan People's Party-S and is a member of parliament.
He told reporters in Peshawar that terrorist attacks would not stop his political activities.
"These attacks are part of my life. These cowardly attacks cannot terrify me," he said.
He has been targeted several times in the past by the Taliban, who accuse Sherpao of carrying out operations against militants and arrested several commanders.
In December 2007, 54 people were killed and over 100 injured when a suicide attacker blew himself up in a packed mosque in Charsadda in a bid to target Sherpao.
Prime Minister Yousuf Raza Gilani strongly condemned the suicide attack on Sherpao and said he was relieved at the news that the former minister had survived.
Islamabad: Former Interior Minister Aftab Ahmed Khan Sherpao and his son had a narrow escape on Saturday when a Taliban suicide bomber blew himself up near their motorcade in northwest Pakistan, killing one person and injuring seven
others, officials said.
First Published: Saturday, March 03, 2012, 20:22