He began playing with his hometown team KF Vllaznimi at an early age before joining KF Liria playing back then in the Yugoslav Second League where he begin playing as senior. He will also play with NK Zagreb and FK Dinamo Pančevo still in Yugoslavia. In 1992 he returned to NK Zagreb, now playing in a newly formed Croatian First League and he will also play with NK Samobor before moving to Belgium.
Hasi moved to KRC Genk in mid-1994, then to TSV 1860 München where he played only seven times during the 97/98 season. He returned to KRC Genk establishing himself in starting lineup, winning the Belgian Title in 98/99 season.
Hasi moved to RSC Anderlecht in May 2000 and, despite only playing 16 matches in his first season due to injury problems, helped the club retain their league title. He played 30 games the following year, including five in the UEFA Champions League to add to his five of the previous season.
Groin and knee problems restricted Hasi to eleven league appearances and four UEFA Cup games in 2002/03, however, but he returned to fitness to help Anderlecht win back the Belgian crown the following season.
In 04/05 season, he suffered torn ligaments in his left knee and was out for 3 months, when he came back he was limited to just 14 starts as Anderlecht relinquished the title.
Hasi moved to Lokeren during the 05/06 season. On Monday June 11, 2007, he signed a two year contract with Cercle Brugge.
He has 50 caps for Albania, in which he scored twice.