Johnson leaves AIK after being cleared of rape
Johnson, who had denied the charge, was cleared by a Stockholm court on Monday after being detained since October.
"Both sides agree that this is the best way to go," AIK's sports chief Jens Andersson said in a statement.
Midfielder Johnson, 26, scored eight goals in 122 games for AIK. He has played in five World Cup qualifiers for Liberia and made his debut for AIK in 2006.
He returned to the Stockholm club last year after a spell at Maccabi Tel Aviv in Israel.