After winning the 2015 U21 European Championship, several teams were interested in the Swedish midfielder. He moved to Italian team Palermo for €2 million (plus €500,000 in add-ons), signing a four-year contract. In "Rosanero", he joined U21 teammate Robin Quaison. He recorded his first Serie A goal on 13 September 2015 against Carpi, a game that ended in a 2–2 draw. Six days later, he scored a brace against Milan, tying the game twice before a 2–3 loss. Hiljemark's brilliant start to the season attracted the attention of bigger clubs. He was linked with Italian giants Milan and Napoli for a possible transfer, as well as Premier League teams Norwich City, Southampton, Watford and West Ham. Towards the end of the 2015–16 Serie A season, Palermo looked to be in danger of being relegated. In the last game of the season, Hiljemark provided a crucial assist for Franco Vázquez in a 3–2 victory against Verona to clinch a spot for Palermo in the 2016–17 Serie A season. Hiljemark played in all 38 matches of Palermo in that season.