At age 13, he transferred played to the youth system of FMP Železnik and Crvena zvezda.

After turning 18, in 2012 he refused to sign a professional contract with the club from Belgrade, only to move to Belgium's Spirou Charleroi.

[3] On June 5, 2015, he returned to Spirou Charleroi,[4] only to part ways with the team in late August.

[5] Following the departure from Spirou Charleroi, he trained with the Serbian team Mega Leks, also playing friendly games with the –team starting with September.

[12] On July 6, 2018, Janković signed a 1+1 deal with Movistar Estudiantes of the Liga ACB.

[13] On December 31, 2018, Janković signed with Serbian club Partizan for the rest of the 2018–19 season.