The role of the UNO was created in accordance with a decision by the military regime of Lieutenant GeneralHussain Muhammad Ershad. In 1982, the Ershad government constituted a committee for administrative reorganization and reform. One of the committee's major recommendations was to create a representative body called Upazila Porishod under a directly elected chair. The government created the position of Thana Nirbahi Officer or TNO later renaming it Upazila Nirbhahi Officer —in each of the existing thanas outside the metropolitan areas. About the same time subdivisions were upgraded and converted into districts, responsibility for all development activities at the local level was transferred to the Upazila Porishads. It was also decided that the UNO should continue to chair the Upazila Porishads until an elected chair took office. UNOs were normally posted from among the officers ranked as "Senior Assistant Secretary" of the BCS Administration cadre.
Charter of duties
;As a CEO of upazila parishad: According to Upazila Parishad Manual and Upazila Parishad Act-1998 Upazila Nirbahi Officer is to perform following duties as a part of CEO and transferred dept. to Parishad.
Act as CEO of Upazila Parishad
As a Chief Executive Officer, UNO is liable to execute all the decisions of Upazila Parishad.
Assist and advice to Chairman to perform his executive responsibilities
Financial disciplines, budgeting and controlling expenditures of the Upazila Parishad
Reporting any unusual matter of upazila parishad to ministries.
Drawing and Disbursement Officer
Monitoring and coordination of development activities
Ensuring govt. interest in the council and calling of meeting etc.
Coordinate of activities of all other departments whether transferred or non-transferred etc.
;As a representative of government: UNO performs some retained and regulatory functions which have not been assigned to Upazila Parishad.
The designation 'upazila nirbahi officer' changed to 'thana nirbahi officer' upon the abolition of the upazila system in the early 1990s. This changed designation again, reverting to 'upazila nirbahi officer' in the late 1990s.
Appointment and regulations
Upazila Nirbahi Officers are appointed by Ministry of Public Administration through B.C.S Cabinet Division directly controls and supervises the activities of UNO.They are the top executive person in an Upazila.