Kammala jumla mai zuwa: Dan asalin Ylitornio, Finland, Koivisto ya koma Rauma tun yana saurayi a 1998 don buga wasa a Lukko, kamar yadda arewacin Finland ba ta da kungiyar SM-liiga a wancan lokacin. Bayan shekara guda da ya yi tare da ƙungiyar Lukko junior A, Koivisto ya fara wasa a SM-liiga a cikin kakar 1999 <unk> 2000, kodayake har yanzu yana raba lokacinsa tsakanin manya da ƙananan ƙungiyoyi. A cikin 2000, Koivisto ya bayyana a Gasar Cin Kofin Duniya ta U18 kuma ya lashe lambar zinare tare da Team Finland. Ya kuma wakilci Finland a gasar 2001 da
Gasar Zakarun Duniya ta 2002, ta dawo gida da azurfa da tagulla, bi da bi.