The bomber targeted the residence of Special Superintendent of Police Chaudhry Aslam of the Crime Investigation Department in the posh Defence area at 7.30 am.
Eight persons, including a woman and a child, were killed by the powerful blast, police officials said. The dead and injured were taken to the nearby Jinnah Hospital.
Aslam, who escaped unhurt, told reporters that several of his police guards were among the dead. He said he had been receiving threats from the banned Tehrik-e-Taliban Pakistan and other militant groups. He vowed that he would not be deterred by such cowardly attacks.
No group claimed responsibility for the attack. The officer and his family were shifted to an undisclosed location soon after the attack.
Aslam had played a key role in operations against militants and criminal gangs and had captured several persons linked to the Taliban and al-Qaeda.
The blast, which was heard from several kilometres away, damaged several nearby houses and cars parked in the area. The explosion caused a ten-foot deep and 25-foot wide crater.
Debris from the officer's home was hurled over a large distance. Footage on television showed the wall and facade of the officer's two-storey building were destroyed by the blast.
A plume of smoke was seen rising into the sky. Several schools and educational institutions are located near the officer's home and the blast was followed by a traffic snarl as parents rushed to the area to pick up their children.
The woman killed in the blast was a school teacher while the dead child was her son, officials at Jinnah Hospital said.
Karachi has witnessed several high-profile terrorist attacks, including one in May on the Mehran naval airbase that killed 10 security personnel.