On 31 January 2014, Källström joined Arsenal on loan for the remainder of the 2013–14 season. Although a back injury was discovered during his medical, it was decided Källström would still join and undergo his rehabilitation at Arsenal. Källström made his debut for Arsenal on 25 March against Swansea City in the Premier League, coming on in the 79th minute as a substitute for Tomáš Rosický. His next appearance came two weeks later in the FA Cup semi-finals against defending champions Wigan Athletic. Introduced as an extra-time substitute, he scored Arsenal's second spot kick in their 4–2 penalty shoot-out win which saw them advance to the final. Källström has gone on to describe this moment as "the greatest 15 minutes of my life." Three days later, he made his first start for Arsenal in a 3–1 victory against West Ham United. Arsenal went on to win the FA Cup; Källström was not in the match day squad for the final. After making four appearance in all competitions, it was announced that Källström would not return to Arsenal once his loan spell with them expired at the end of the season. Despite only making four appearances, Källström said he enjoyed his time at Arsenal.