Mehmeti made his Allsvenskan debut on 31 March 2008 against IFK Göteborg. His first goals came in dramatic style. With Malmö FF trailing Kalmar FF 2–1, Mehmeti was subbed on in the 83rd minute. He struck net twice, lifting Malmö to a 3–2 victory. In 2009 Mehmeti fought for a starting spot but retained his role as the super-sub as he scored 5 goals coming on as a substitute. In 2010 Mehmeti finally took a starting spot, starting 23 out of 30 possible. He was Malmö FF's top goalscorer for their league winning season in 2010 when he scored 14 goals of which 11 were league goals. Mehmetis 2011 season was not as successful as his previous ones. Troubled by light injuries and his contract running out at the end of the season he scored four goals in 21 matches for the 2011 Allsvenskan. Mehmeti chose not to renew his contract after the 2011 season.
Palermos director of sports Luca Cattani confirmed the signing of Mehmeti on 9 November 2011. Mehmeti joined the club on 1 January 2012 when the transfer window opened. On 11 November 2011 Mehmeti also confirmed a five-year deal with Palermo, which makes him a Palermo player until 30 June 2016. Mehmeti made his debut for Palermo in the home fixture against Napoli on 8 January 2012. He made a further two appearances from the bench during the 2011–12 season.
On 30 August 2012, he moved on loan to Novara in exchange for Italian winger Luigi Giorgi. Mehmeti stayed at Novara for the remainder of the 2012–13 season where he played 23 matches and scored six goals for the club.
In July 2013 it was announced that Mehmeti would go to SC Olhanense in the Portuguese Primeira Liga for a season long loan deal. On 24 August he scored his first goal for the team in his second league game. In total Mehmeti played 20 matches while at Olhanense and scored twice.
On 15 July 2014 Malmö FF announced that they had reacquired Mehmeti on a three-and-a-half-year-long contract, making his return after two seasons abroad in Italy and Portugal, after having been released for free by his last club Palermo earlier the same day. For the remainder of the season Mehmeti made 10 league appearances, five of them in the starting line-up. He also scored twice, both goals in the away match against Falkenbergs FF on 2 August 2014. He also made four appearances in the clubs campaign in the 2014–15 UEFA Champions League.
Mehmeti then moved across the border to Norway and played in 24 league games for Stabæk, in the 2016 season. He scored 4 goals that year after making his debut against Molde.
After this, the striker moved to the Turkish capital Ankara, to play for Gençlerbirliği. However, he played only two Süper Lig games for them before joining the English League One side Oxford United, on 7 September.
Mehmeti has played for the Swedish Under-21 side, but he told the Albanian media that he was eligible to play for either Sweden, or Albania in the future. In July 2013, Mehmeti was called up to the Albania squad for their final World Cup qualifying matches. On 4 June 2013 he received Albanian citizenship, as did Albania U21 players Amir Rrahmani, Haxhi Neziraj, Valentin Gjokaj and Herolind Shala. He was selected by the Albanian national coach Gianni de Biasi for the World Cup qualifying matches against Slovenia and Iceland in September 2013.
Mehmeti was born in Podujevo (Albanian: Besiana), then still part of SAP Kosovo, SR Serbia within SFR Yugoslavia. At age two he moved with his family to Valdemarsvik, Sweden, and they later settled in Malmö. He is of Albanian descent. Mehmeti played for Sweden U19 and Sweden U21 before deciding to play for Albania.As of 8 September 2017.
As of 15 October 2013.
Allsvenskan: 2010, 2014
Svenska Supercupen: 2014