Kir was born on 17 October 1968 in Charleroi, Wallonia,[2][3][4] the son of Muslim Turkish immigrants who came to work in the Belgian mines as guest workers in the 1960s.

[5] With a working-class background and admiration for Guy Cudell (mayor of Saint-Josse-ten-Noode for over forty years), he joined the French-speaking Socialist Party (PS) in 1995.

[2][5] In 2004, following the regional elections, in which he achieved an unexpected score: 7,000 preferential votes (second PS score behind Charles Picqué), he left his post as alderman to become Secretary of State for Monuments and Sites and Public Cleanliness in the Brussels government,[2][3][5] as well as Minister of Social Action, Family and Sport in the French Community Commission (COCOF).

[6] In 2006, he took part in the local elections, winning more votes than the then-mayor Jean Demannez,[7][5] but did not (yet) claim the maïorate, as he was still Secretary of State in the Brussels government, becoming instead first alderman.

[4][19][3][20] In April 2019, when interviewed by Al Arabiya of Saudi Arabia, Kir compared Belgium to Nazi Germany for the Plan Canal, a large revitalization program which also included an initiative against Islamic extremism in Brussels.

[22] In April 2024, Kir issued a ban on the right-wing National Conservatism Conference to be held in Saint-Josse-ten-Noode, citing "ensuring of public security" and saying that the "extreme-right is not welcome" in Brussels.

[24] The ban was legally challenged by the organizers and the Council of State subsequently allowed the conference to continue, in compliance with freedom of speech guaranteed in Article 26 of the Belgian Constitution.