On-loan Chelsea defender Reece James was captain for the day and got a standing ovation when Wigan boss Paul Cook took him off late on
Joe Garner scored the only goal as Wigan ended their first season back in the Championship with victory over Millwall.
With both sides safe from relegation, there was a predictably flat atmosphere inside the DW Stadium.
But Garner lifted the mood with what was to prove the only goal of the game when he smashed home left-footed after Nick Powell's shot was parried by Millwall keeper David Martin.
The visitors thought they had levelled when Ryan Leonard converted from Shaun Williams' corner only for the referee to award Wigan a free-kick for a foul.
And the Lions went close again when Jake Cooper stabbed the ball goalwards only for Powell to clear off the line.
Top scorer Lee Gregory - who Millwall boss Neil Harris afterwards confirmed had played his final game for the club - forced a fine save from Wigan keeper Christian Walton, but Millwall were unable to find a way through.
Wigan, whose victories over third-placed Leeds and Preston over Easter lifted them away from danger, took off captain for the day Reece James late on, to allow the on-loan Chelsea youngster a standing ovation.
Paul Cook's side, League One champions last season, finish 18th, nine points clear of the relegation zone, with Millwall 21st, four points better off than relegated third-from-bottom side Rotherham.
Wigan manager Paul Cook:
"I'm delighted for the players, I really am. The home form's been so good, especially in the latter stages of the season. In fact, it's probably been up there with some of the teams that have made it to the play-offs.
"Unfortunately the away form - with the same players and the same habits - hasn't been as good, and that's been a challenge.
"But to end up with 52 points in this league, it's such a reward for the efforts we've put in as a group and a staff."
Millwall manager Neil Harris:
"I have to say I quite enjoyed the game. As a neutral, it was quite entertaining. It could have been 4-4 if both sides had taken their chances.
"We played a little bit more expansive football than we have done. I wanted the players to pass the ball a bit more than we have been doing, and I knew it would leave us open at the other end.
"I can only thank Lee Gregory for his efforts while I've been in charge. Not just his goalscoring record but his quality as a person. Hugely popular in the changing room with players and staff. We're going to miss him immensely, but he goes with our complete blessing. It would be a great signing for somebody."
