The International Security Assistance Force (ISAF) identified the militant as Dilawar, a lieutenant of Haji Mali Khan, said to be the senior leader in Afghanistan and whose capture the military announced last week.
Dilawar, who like many Afghans goes by one name, “was a principal subordinate to Haji Mali Khan… Dilawar was killed exactly one week following Khan’s capture,” ISAF said in a statement.
His death was “another significant loss for the insurgent group,” it added.
The military accused Dilawar of coordinating attacks against Afghan forces and moving weapons along the Afghan-Pakistani border.
The feared Haqqani network has its main powerbase in eastern Afghanistan but its leadership is based across the border in Pakistan’s lawless tribal belt.
Afghan and US officials accuse the network over a string of high-profile attacks in heavily-guarded Kabul, including last month’s 19-hour siege which targeted the US embassy and ISAF headquarters.
Dilawar was killed in the eastern province of Khost on Tuesday, ISAF said, stressing no civilians were injured in the operation.