[1] After little success in Turkey he returned to Albania and played for Tirana[2] where he scored 15 league goals in 37 games before joining Sparta Prague in the Czech Republic in January 2013.

During his time at Sparta Prague he was loaned out to Polish side Jagiellonia Białystok for the entire 2013–14 campaign where he scored 9 goals in 36 games in all competition before return to his parent club for the first half of the following season.

He made his international senior debut in 2012 and played an important role in Albania's successful UEFA Euro 2016 qualifying campaign, notably scoring the winner with a volley in the opening day against Portugal.

[5] Balaj joined his hometown club Vllaznia as an 11-year-old in 2002, and his father had told the youth team coach Astrit Premçi to initially test the player as a goalkeeper as he was tall for his age.

With the departures of Xhevahir Sukaj and James Boadu ahead of the 2009–10 season, Balaj became the club's main striker alongside Vioresin Sinani.

He made his European debut on 2 July 2009 against Irish club Sligo Rovers, coming on as an 85th-minute substitute for Vioresin Sinani in the 2–1 away win.

[14] But after meeting with Refik Halili he signed a two-year contract for Tirana on 20 January 2011, earning €70,000 a season, which was a higher offer than Vllaznia's €50,000.

[2][15][16] He made his debut for his new club on 3 February in a home match against Skënderbeu which ended in 0–0 draw, with Balaj coming on at the start of the second half for Gilman Lika.

On 4 October 2012, Balaj scored an historical goal in his career at UEFA Europa League against Athletic Bilbao, a match valid for group stage finished in the victory 3–1.

[3][41] On 11 February 2015 Balaj made his competitive début in Rijeka's 4–1 win against NK Lokomotiva in the first leg of the Croatian Cup quarter-final, also scoring his first goal for the club.

[43] Balaj scored his second goal in the second league game in a row and third including both championships against RNK Split in the 56th minute of the match, to give his team the 1–1 draw.

[44] During the season, Balaj scored 9 goals in 15 appearances, helping Rijeka to finished as runners-up and secure a place in the 2015–16 UEFA Europa League - Second qualifying round.

[47] A few days later Balaj made his European debut for Rijeka playing the full 90-minutes in the 2015–16 UEFA Europa League Second qualifying round first-leg match against Aberdeen.

On 8 June 2016, Balaj completed a move to Russian Football Premier League side Terek Grozny for €550,000, signing a three-year contract with the option of another year.

[50] Balaj made his debut for the club on 31 July in the opening league match against Krylia Sovetov, playing for 59 minutes in an eventual 1–0 home win.

[58] Balaj started the 2017–18 season by providing an assist for the 1–0 winning goal against FC Amkar Perm on 16 July 2017 scored by Léo Jabá.

[63] On 18 January 2023, Vllaznia announced to have signed Balaj on a three-year contract, with the striker returning to his hometown club after thirteen years.

[69] Balaj was called up at Albania national under-20 side by coach Artan Bushati to participate in the 2009 Mediterranean Games football tournament, which began on 25 June in Pescara, Italy.

[73] Balaj was called up for the first time in competitive matches for Albania for the 2014 FIFA World Cup qualification two closing games against Switzerland and Cyprus on 11 and 15 October 2013.

[80] In the 2018 FIFA World Cup qualification opening match against Macedonia on 5 September 2016, Balaj came in as a 60th-minute substitute replacing the Midfielder Amir Abrashi to play in the attack line forming a duo partnership among Armando Sadiku.