Helander made his Allsvenskan debut in a match against Syrianska on 17 October 2011.[3] Helander played the first matches beside Pontus Jansson in defence before being replaced by Daniel Andersson after the second round of matches. On 17 July 2012, Helander signed a first team contract with Malmö until the end of the 2015 season.[4] When Andersson played less and less after the summer break Helander established himself in the starting lineup and finished the season as a regular starter in the defence. Helander played a total of 12 league matches for Malmö during the 2012 season.[citation needed]
The league title winning 2013 season proved to be the real breakthrough season for Helander as he played 18 matches for the club.[citation needed] He was injured in the early stages of the season and was replaced in the starting line-up by Erik Johansson but later reclaimed this spot in the second part of the season.[citation needed] For the 2014 season Helander played regularly throughout the entire season as the club defended their league title and qualified for the group stage of the 2014–15 UEFA Champions League.[citation needed] He also scored his first league goal for Malmö in 2014 on 23 August in a 3–0 home win against IFK Norrköping.[5] For his performances in the league Helander was nominated for the award of Allsvenskan defender of the year.[6] He was also nominated for Swedish defender of the year at Fotbollsgalan.[7]
Hellas Verona
On 22 July 2015, Helander signed for Hellas Verona in the Italian Serie A.[citation needed] On 23 September, he made his debut against Internazionale in a 1–0 defeat at the San Siro.[citation needed] In the next game against Lazio at home he again was in the starting line up and in the 33rd minute he scored his first Serie A goal.[citation needed] Lazio went on to win the game 2–1.[citation needed]
Bologna
On 31 August 2016, Helander joined Bologna on a season-long loan deal, with an obligation to sign outright at the end of season. As part of the deal, Nicolò Cherubin moved to Verona.[8] On 12 June 2017, Helander joined Bologna on a definitive basis.[9]
The following season, his second with the Rossoblù, Helander found more space in the rotation under coach Roberto Donadoni, playing 29 games.[citation needed] His club season ended early in April 2018 because of an injury, but without risking the World Cup in which he participated as a reserve.
On 11 March 2021, Helander scored the equaliser for Rangers in a 1–1 draw away to Slavia Prague in their Europa League Round of 16 first leg match.[13]
On 29 August 2021, Helander scored the only goal of the game for Rangers against Celtic in the first Old Firm derby of the 2021–22 season.[14] On 15 September 2021, Rangers manager Steven Gerrard announced that Helander would be out for the foreseeable future after having undergone surgery on a knee injury sustained in a 2–1 win over St Johnstone four days prior.[15]
Rangers confirmed on 23 May 2023 that Helander would leave the club at the end of the 2022–23 season.[16]
OB
On 31 August 2023, Helander joined Danish Superliga side OB on a one-year deal.[17] Made his debut in a 3-0 defeat to Silkeborg IF on 18 September 2023.
^"En debut att minnas för Helander" [A debut to remember for Helander]. Sydsvenskan (in Swedish). 17 October 2011. Archived from the original on 21 October 2011. Retrieved 18 October 2011.
^"Nomineringarna till Fotbollsgalan 2014" [Nominations for the Football Gala 2014]. Fogis.se (in Swedish). Swedish Football Association. 20 October 2014. Retrieved 19 January 2015.