Karkare obtained a Bachelor of Engineering degree in Mechanical Engineering from Visvesvaraya National Institute of Technology, Nagpur. After graduation he worked for Hindustan Lever Limited, India's largest consumer product company.
He joined the Indian Police Service (IPS) as a member of the 1982 batch. Among the posts he held in the IPS was that of Additional Commissioner of Police. He served seven years in Austria in the Research and Analysis Wing (RAW), India's external intelligence agency. On his return in January 2008, he was appointed the head of Maharashtra's Anti-Terror Squad (ATS).
On September 29, 2008, three bombs exploded in Modasa, Gujarat and Malegaon, Maharashtra killing eight persons, and injuring 80. Several unexploded bombs were found in Ahmedabad, Gujarat. Hemant Karkare, as the chief of the state Anti-Terror Squad, led the investigation into the 2008 Malegoan blasts.In late October the ATS arrested eleven suspects, and alleged that some radical Hindu groups were behind the blasts.
Opposition parties, including the Bharatiya Janta Party and Shiv Sena, and Hindu organizations alleged that the arrests were made under the pressure of the incumbent government, in an attempt to appease India's Muslim population.Karkare came under intense political pressure during the investigation, and some BJP, RSS and VHP leaders accused the ATS of being used as a tool to attack the Sangh Parivar and of using illegal detention and torture.
Hemant Karkare was killed in action by militant terrorists during the Mumbai attacks, on 26 November, 2008.
India Express quotes statements by Constable Arun Jadhav, who was with the officers Hemant Karkare, Vijay Salaskar and Ashok Kamte when they died.The three officers and four constables had received information that Sadanand Date had been injured in the gunfire at the Cama and Albless Hospital for women and children. Located at Chhatrapati Shivaji Terminus (CST), a ten-minute drive from the hospital,they took a Toyota Qualis and proceeded in that direction. Salaskar was driving, Kamte in the passenger seat, Karkare in the second row, and the four constables, including Jadhav, were in the back row of seating. According to Jadhav, five minutes later two terrorists stepped out from behind a tree and opened fire with AK-47 automatic rifles. The six policemen, other than Jadhav, were all killed quickly in the gunfire. The wounded Jadhav had no opportunity to render assistance. The two terrorists approached the vehicle, dumped the bodies of the three officers on the road and, leaving the constables for dead, proceeded to Metro Cinema. Upon arrival, they aimed three bursts of automatic fire at police and journalist vehicles drawn up at that location, then drove off towards the government offices (Vidhan Bhawan) in South Mumbai. Here again they fired several times. While attempting to leave the area, one of the tires of the vehicle burst, so the terrorists departed to obtain another. At this point, Jadhav was able to contact headquarters. The bodies of the dead were promptly recovered and taken to St George Hospital.
His bravery was honoured with the Ashoka Chakra on 26 January 2009.