Gillingham suffered relegation to League One as Eugen Bopp's late goal secured a draw for Nottingham Forest.
Crewe's dramatic 2-1 win against Coventry and Brighton's draw with Ipswich ensured the Gills dropped out of the Championship on goal difference.
Wes Morgan gave Forest the lead, bundling in at the second attempt but Andrew Melville put through his own net to draw the Gills level.
Mamady Sidibe steered Gillingham ahead but sub Bopp's fine shot made it 2-2.
The Gills had to win to be certain of staying up and despite going a goal down early on their chances looked good as Crewe also trailed at home to Coventry at the break.
But Crewe's superb comeback, coupled with some sloppy Gillingham finishing ensured there were no last-day heroics for Stan Ternent's men.
Forest should have gone ahead after seven minutes when Neil Harris, who replaced Scott Dobie up front in one of four changes for the home side, fired wastefully over from six yards.
Gillingham, who dropped striker Darius Henderson to play Andrew Crofts in a five-man midfield, also had their moments in attack and Michael Flynn's 20-yard shot forced a smart save from keeper Colin Doyle.
But Gary Megson's side took the lead when Morgan bundled in from close range at the second attempt after 29 minutes.
Nyron Nosworthy fouled Gareth Taylor and when Kris Commons whipped in the free-kick, Gills keeper Brown parried Morgan's initial header but was powerless to prevent him knocking in the rebound.
Gillingham piled forward in the closing minutes of the first half with both Paul Smith and Crofts testing Doyle, while Jonathon Douglas also saw a shot go wide.
Henderson replaced Flynn as Gillingham ditched the defensive approach after the break and the match fired into life.
Stan Ternent's substitution brought an immediate reward when Nicky Southall got to the bye-line and his cross was slid into his own net by Melville from six yards.
Henderson then missed two glorious chances to put the visitors ahead.
It didn't seem to matter though as Gillingham - wary of the need to win as news filtered through that Crewe were leading at Gresty Road - took the lead with 13 minutes to go, Sidibe volleying home after another fine cross from Southall.
But Forest substitute Bopp bagged a dramatic equaliser with five minutes to go, blasting in a superb 25-yard strike with his first touch.
There was still time for Forest's Gareth Taylor to see a header come back off the bar.
And Gillingham also had two excellent chances to grab the goal that would have preserved their Championship status.
First Henderson rounded Brown but was thwarted by a last-ditch challenge with an open goal at his mercy.
And fellow sub Darren Byfield saw an effort blocked in injury time.
Nottingham Forest boss Gary Megson:
"I honestly, hand on heart, didn't know the permutations of Gillingham, Brighton and Crewe.
"We messed it up last week and therefore we were not even part of that equation so I didn't get involved in it. It's like being at someone else's party.
"Ten contracts come to an end now. I want to deal with that as soon as I can."
Nottm Forest: Doyle, Louis-Jean, Morgan, Melville, Curtis, Gardner, Evans, Perch (Bopp 85), Commons, Harris, Taylor.
Subs Not Used: Roche, Robertson, Beaumont, Hjelde.
Goals: Morgan 29, Bopp 85.
Gillingham: Brown, Nosworthy, Cox, Ashby (Byfield 86), McEveley, Southall, Smith, Crofts (Jarvis 45), Douglas, Flynn (Henderson 55), Sidibe.
Subs Not Used: Banks, Hessenthaler.
Goals: Melville 61 og, Sidibe 77.
Ref: R Styles (Hampshire).