On 11 August 2007, Marjanović made his Serbian SuperLiga debut in a 0–0 away draw against Red Star Belgrade.
[8] Four days later, Marjanović made his debut in UEFA club competitions playing full 90 minutes against Ulisses and providing one assist in 0–1 away win.
He also stayed with the club in new season, and became one of the most important players in midfield for coach Milan Rastavac, along with Aleksandar Jovanović and Petar Đuričković.
[14] In next fixture, he scored a goal for first win of FK Radnički against Partizan on the Čair Stadium after 22 years.
[17] After 8 matches at total he collected under coaches Ivan Tomić and Marko Nikolić in the first half-season, he missed the rest of the campaign in both domestic competitions.
[18] In the mid-season, Marjanović mutually terminated the contract with Partizan and left them as a free agent on 10 January 2018.