CSN reports that Akas last featured for Nigeria Professional Football League club Enyimba Football Club of Aba.
The left-back impressed while on trials at the Swedish club at the end of last year and has now been rewarded with a permanent deal.
The former Shooting Stars player turned down the chance to feature for Nigeria at the African Nations Championship currently going on in Morocco to secure the move.
He was captain of the Nigerian team at the CHAN 2016 in Rwanda and was later made vice-captain with goalkeeper Ikechukwu Ezenwa taking over the role during the qualifiers for CHAN 2018 and WAFU Nations Cup in Ghana.
The 23-year old spoke about his quality as a defender after completing the move.
“I’m a fast-paced player who plays as a left back,” he told Kalmar FF’s official website.
“I’m also a good ball winner and a good crosser as well.