Starting out at Landskrona BoIS in the early 2000s, he went on to represent clubs in France, Germany, Denmark, Switzerland, and Italy before retiring at FC Chiasso in 2022.

[15] After a difficult start to the season, in which he was often benched, Farnerud became a regular and consistent performer for Toro,[16] netting again in the 14th round against Genoa and two days later against Udinese.

[17] On 9 August 2016, Farnerud returned to his native country, signing a long-term deal with BK Häcken[18] and re-joining his childhood friend Rasmus Lindgren at his new club.

[19] He played 11 matches and scored three goals in his debut campaign, and went to provide eight assists during his spell before attracting a serious knee injury in a fixture against IK Sirius on 22 July 2017; due to his recurrent physical ailments, he chose to leave by mutual consent in November.

[28] He won his first cap for the Sweden national team on 16 February 2003 at age 18, in a King's Cup fixture against Qatar; four days later, in the same competition, he scored his first goal to help to a 2–0 defeat of Thailand.

[29] On 21 March 2015, after more than five years of absence, Farnerud was called by manager Erik Hamrén for a Euro 2016 qualifier against Moldova and a friendly with Iran.