Goals from Ivan Toney and Emiliano Marcondes saw the Bees finally break their play-off hoodoo.
It was swift redemption for Thomas Frank’s side, back at Wembley Stadium just nine months after losing to Fulham in last season’s delayed final.
There was to be no repeat of that heartbreak for the Bees, who in securing promotion will become the 50th different club to play in the Premier League.
They also ended the so-called curse of the red and white stripes, which has seen teams in Brentford’s colours feature in 33 play-off campaigns without achieving promotion. Lincoln, playing Blackpool in Sunday’s League One final, will surely have taken note.
It was somehow fitting that Brentford put paid to those statistical anomalies, given how their success is underpinned by a data-driven recruitment policy, and now the west London number-crunchers can factor an extra £160million or so into the kitty.
It was also fitting that Toney, who has flourished after being brought in at the start of the season to fill the void left by the sale of star players Ollie Watkins and Said Benrahma, was the man to open the scoring.
Just 10 minutes had elapsed when Bryan Mbeumo darted between two defenders to reach a through ball from Sergi Canos and was wiped out by Swans goalkeeper Freddie Woodman.
Toney had not missed a penalty all season and he was not about to start now, the prolific striker slotting his 33rd goal of the season into the bottom corner.
It was the start Swansea, so tight at the back but not exactly prolific in attack, would have dreaded – and things quickly got worse.
When Andre Ayew was dispossessed in the Brentford penalty area in the 20th minute Mbeumo was able to race upfield unchallenged.
Assistance arrived in the overlapping Mads Roerslev, who lifted the ball across goal for Marcondes to slam home first time.
Swansea were reeling and their noisy band of 5,000 supporters, among a restricted crowd of 11,689, were almost silenced when Toney chested the ball down before seeing his volley hit the underside of the crossbar.
Ayew looped a header onto the bar before half-time and then glanced another inches wide at the start of the second half as Swansea looked for a way back.
But their chances all-but ended in the 65th minute when Jay Fulton was shown a straight red card for an ugly-looking, but clumsy, lunge on Mathias Jensen.
It was a sad end to a fine campaign for Swansea and their manager Steve Cooper as they succumbed to Brentford in the play-offs for the second successive season, having lost last year’s semi-final.
But for Frank – the first Danish manager to win a promotion in England – and his forward-thinking club, the top flight beckons for the first time since 1947 and their new Community Stadium, empty for the majority of its maiden season, will be abuzz with Premier League football in August.