JOIN USQasab was critically injured during the Swat operation and he succumbed to his injuries, Geo TV reported.
Swat media said the commander was nabbed four days ago from Charbagh area. He had reportedly confessed to murdering several people including government officials.
Three sons of Qasab had been killed in earlier assaults by troops in the same area.
Qasab's arrest Wednesday came four days after the military announced the capture of the Taliban spokesman in Swat, Muslim Khan, with four militants.
Military operations began April 26 after the Taliban reneged on a controversial peace deal with the NWFP government under which they were to lay down arms in return for Sharia laws being imposed in the Malakand division, which includes Swat, Buner, Lower Dir and four other districts.
Instead, they moved south from their Swat headquarters and occupied Buner, which is just 100 km from Islamabad.
The operations started from Lower Dir, home district of radical cleric Sufi Mohammad, who had negotiated the peace deal and who is the father-in-law of Swat Taliban commander Maulana Fazlullah. The focus later shifted to Buner and Swat.
The military says over 1,500 Taliban have been killed in the operations.