Douglas finished his contract at Leeds last summer to complete a switch to Poland with Lech Poznan on a free transfer.
The left-back was keen to secure regular game time which eluded him at Elland Road; he spent his last year as a Leeds player on loan at Blackburn Rovers.
Now Douglas has helped Lech Poznan to clinch the Polish league title and he took to social media to celebrate winning the trophy again.
Douglas was part of the Lech Poznan side that won the title in 2015 and has now helped the club end the drought this year.
He clocked up 18 appearances across all competitions for Lech Poznan this season.
The defender has a further year left on his contract in Poland and will ow be looking to help Lech Poznan make progress in the Champions League.
Lech Poznan will enter the Champions League in the first qualifying round stage.