Song, 33, joined Djibouti club AS Arta Solar 7 last November after being released by Swiss outfit Sion.
He has now captained the north-east African side to their first ever top-flight crown.
Arta Solar beat second-placed AS Port 4-2 last Friday to seal the title with two matches left to play.
Song said: "It's mission accomplished, and I am delighted. Coming here wasn't easy.
"There are things you don't know about when you arrive in a new country, but thank God it has gone well.
"I am proud for the club president, who has given me the opportunity to come here. He has achieved something historic."