Aly Keita has played for seven years in the club and has been involved in taking ÖFK from the Superettan to the Allsvenskan, winning the Swedish Cup and playing the Europa League finals.
He has also been mentioned as one of Allsvenskan's best goalkeepers.
- It feels good to have it ready, I am charged and looking forward to these three years, he says in a video on ÖFK's website.
Keita says that he has had other offers but says that it was only ÖFK that applied to him.
On Sunday, Östersunds FK will host IFK Gothenburg at home.