The incident took place on Sunday afternoon in Gardez City, the provincial capital of Paktia.
The victim was identified as Haji Zuhruddin who was a tribal elder in Syed Karam district of the province.
Provincial police spokesman Sardar Wali Tabasom said the individual was a member of local police in the past and had personnel enmity.
This is the second similar incident in the province during the last couple of days.
On Friday night, unidentified gunmen shot dead a judge in Ahmad Abad district of the province.
No individual or group has claimed responsibility of the attacks yet.