Gary Johnson's team will ply their trade in the second tier of English football for the first time in their history after edging past the Bees in a tense encounter at Wembley
First-half goals from Paddy Madden and Daniel Burn gave the Glovers a comfortable half-time lead against a misfiring Bees outfit.
Uwe Rosler's men came out rampant in the second half and pulled one back through Harlee Dean but despite their herculean efforts after the break they couldn't find the elusive second.
Both Rosler and Glovers boss Gary Johnson named the same XI that saw their respective sides through the second leg of their semi-finals against Swindon and Sheffield United.
League One top-scorer Madden made an electric start to the game and gave the Glovers a deserved early lead with a superbly taken goal. His first effort was blocked as he spun and shot inside the box in the fifth minute but moments later the Irishman wasn't to be denied.
The ball deflected into his path, the Yeovil striker managed to beat Simon Moore with a delicate flick, using the outside of the boot to send the ball into the top corner to give Johnson's side the perfect start.
Buoyed on by their vocal support, the Bees then tried to force their way back into the game. Rosler's side were camped in the Yeovil third for a period of 15 minutes or so but never managed to find the penetration required to level the score, despite a succession of corners and free kicks.
Harry Forrester, Brentford's main goal threat, had a frustrating first half. He showed plenty of effort and industry but never managed to create himself a clear goalscoring opportunity to haul the Bees back level.
All of that pressure counted for nothing though as when the half drew to a close Burn broke Brentford hearts by doubling Yeovil's lead. After a couple of goalmouth scrambles the Glovers defender managed to turn the ball past Moore after Hayter's front-post flick-on from a corner.
The Bees almost pulled one back before the break but Marcello Trotta's header was brilliantly kept out and held by Marek Stech after a fine cross from Jake Bidwell.
Whatever Rosler had to say to his players at half-time, it worked.
The Bees came out buzzing and got the goal they so desperately craved in the 51st minute. Dean drifted into the box to turn home Adam Forshaw's well delivered corner with a thumping header to reignite Brentford supporters' hopes.
Bradley Wright-Phillips was inches away from grabbing the equaliser later in the half but he could only watch as Clayton Donaldson's header trickled agonisingly wide of the post.
Seconds later Forshaw was played clean through on goal but he could only direct his shot straight at the grateful Stech.
A final gilt-edged chance fell to Wright-Phillips but his volleyed effort on the spin was well blocked by Stech.
It proved to be the final real scare for Yeovil despite six added minutes; Johnson's Green Army are going up and will play in the second tier for the first time in their history.