SerbiaA product of the Rad youth system, Mladenović was promoted to the first-team squad in the second part of the 2014–15 Serbian SuperLiga, making 11 appearances and scoring one goal.
On 5 August 2019 it was confirmed, that Mladenović had joined Portuguese Primeira Liga club Gil Vicente.
On 22 January 2020 Mladenović signed for Serbian SuperLiga club Vojvodina.