Hanachi, Tehran Municipality’s deputy for urban development and architecture, was elected to the post with 11 votes on Tuesday.
His main challenger was former minister of roads and urban development, Abbas Akhoundi, who received 10 votes from the councilors.
Hanachi, 54, will replace Mohammad-Ali Afshani, who was required to leave the post under a recently-adopted law that bans retirees from being employed in government positions.
The Interior Ministry still has to sign off on Hanachi’s win.
The position has been historically synonymous with mammoth responsibilities.
The city proper hosts a population of close to nine million. The population in its entire metropolitan area, known as Greater Tehran, reaches some about million – making it the 29th biggest in the world.