Born in Miratovac, a small town in the municipality of Preševo as a member of Albanian ethnic group,[3] Zulfiu started playing football at the age of 10.[7] He was playing with football club Lugina, based in Aliđerce,[4] until he joined Radnik Surdulica as a youngster.[3] After almost two years with youth team, Zulfiu signed a one-year scholarship contract with Radnik in February 2017.[8] He was also loaned on dual registration to the Serbian League East side Pukovac,[9] making six appearances until the end of the 2016–17 campaign.[10]
In summer 2017, Zulfiu joined the first team of Radnik Surdulica under coach Simo Krunić,[11] but moved on new loan deal to Ozren Sokobanja shortly after.[12] He scored his premier goal for the first season victory of Ozren over Timok on 16 September 2017.[4] After the whole first-half season in the third-ranked league, a loan deal was terminated and Zulfiu returned to Radnik ending of November same year.[13]
On 29 November 2017, Zulfiu made his official debut for Radnik Surdulica, replacing Miloš Stanković in 69 minute of the Serbian SuperLiga match against Red Star Belgrade.[14] He has been reported as the first Albanian footballer in the club history since finding in 1926.[15] In February 2018, Zulfiu signed his first four-your professional contract with Radnik,[16] after which he extended his loan deal to Ozren until the end of 2017–18 campaign.[17]
Returning from loan deal in summer 2018, Zulfiu started new season preparing under coach Mladen Dodić,[18] but after being excluded from the 2018–19 Serbian SuperLiga player list, Zulfiu mutually terminated the contract and left Radnik as a free agent on the last day of July same year, along with teammate Krsta Đorđević.[19]
^Jovanović, M. (27 June 2018). "Leskovčanin Stanković ponovo u Radniku" [Stanković from Leskovac returned to Radnik] (in Serbian). juznevesti.com. Retrieved 2 August 2018.