Paul Merson's bid to guide Walsall to safety ended in failure as the Saddlers were relegated despite recording their first win in six games against Rotherham at the Bescot Stadium.
Walsall's fate was sealed when Gillingham managed to avoid defeat at Stoke City.
Walsall had needed to win by three goals in the event of a draw at Stoke but that just proved beyond them as they were forced to play the final 29 minutes of the game with just ten men after the dismissal of Simon Osborn.
Walsall had failed to score in five games before facing Rotherham but set up a barnstorming second-half when Osborn fired them in front after 48 minutes.
But Osborn went from hero to zero in the space of just 13 minutes as he conceded a penalty and was then sent-off after collecting two bookings.
Osborn gave Walsall the lead when he bundled home a Lee Bradbury cross from just two yards.
It looked set to spark a dramatic second-half onslaught by Walsall but their survival hopes effectively came to an end when Rotherham equalised from the spot six minutes later.
Walsall were left fuming when referee Brian Curson pointed to the spot after a challenge by Osborn on Scott Minto.
It was the third penalty that Walsall had conceded in successive games and Michael Proctor coolly slotted the ball past James Walker.
Osborn was booked for his challenge on Minto and his misery was then completed seven minutes later when he was dismissed after collecting a second yellow card for a challenge on Andy Monkhouse.
That looked to be the end of Walsall's brave survival fight but they continued to carry the game to Rotherham and were rewarded after 70 minutes when Mark Wright struck just two minutes after being sent on.
Wright pounced after goalkeeper Mike Pollitt had spilled a long-range shot from Jorge Leitao.
Wright then bundled the ball home from close range but it was too little too late for Walsall whose three-year first division adventure came to an end.
Substitute Paul Warne looked to have earned Rotherham a point when Walsall conceded yet another penalty in the last minute after Ian Roper was adjudged to have fouled Richard Barker.
But never-say-die Walsall at least ensured that they went down with all guns blazing when Paul Ritchie's injury-time header from Merson's corner earned them an ultimately fruitless win.