With the Latics having the small matter of an FA Cup semi-final against Arsenal to look forward to this weekend, Ian Holloway's men took full advantage to hand Uwe's Rosler his first home defeat in the DW hotseat.
Right from the off the visitors were the livelier and asking by far the more probing questions.
Lee Martin thumped an early free-kick into the Wigan wall, before setting up Martyn Woolford, whose weak header was easily saved by the returning Scott Carson.
With Wigan struggling to put two passes together, Millwall took the lead after 22 minutes when Edwards carried the ball half the length of the pitch before pulling the trigger from just outside the box.
The shot took a wicked deflection off Leon Barnett which completely wrong-footed Carson, who could only watch as the ball looped over his head and into the net.
Martin curled another effort just over the bar, before Wigan got themselves a foothold in the game.
Former Millwall loanee Martyn Waghorn headed wide and Nicky Maynard volleyed just past the upright, before the latter fired over the top from a good position.
Wigan almost levelled it just before the break when a free-kick was only half-cleared to Jack Collison, whose shot was well saved by the legs of David Forde.
Wigan made two changes at the break to try to up the tempo, Marc-Antoine Fortune and James McArthur for Maynard and Josh McEachran.
And the initial signs were good as Fortune headed just wide of Forde's goal.
Nick Powell took over from James McClean for the final third, but still the Lions were keeping their high-flying oppoents at arm's length with relative comfort.
Powell almost scored with his first touch after Forde flapped at a cross and sent the ball straight to the on-loan Manchester United man, whose shot was deflected over the top.
The same player then fired wastefully into the stand, and Wigan knew it wasn't to be their day when Jean Beausejour cleverly found Collison 12 yards out, but the midfielder's shot curled inches past the post with the goalkeeper beaten.
And Milllwall nearly doubled their advantage in the closing stages when Scott Malone's blockbusting drive was parried away by Carson, who then kept out the follow-up from Steve Morison right on the goalline.