The former Glasgow University student picked up the main prize, best album, for Our Version Of Events after collecting the best female solo artist prize.
The 25-year-old – up for three trophies – beat stars such as Jessie Ware and the late Amy Winehouse to land the album award.
Picking up the Damien Hirst-designed trophy from US star Taylor Swift, Emeli said: "This feels amazing. This is incredible. I'm so happy to win this award."
The beaming star collected the prize a year after she won the Critics' Choice Award at the Brits.
She was at the O2 Arena among the cream of British and international stars for last night's event.
Sande went on: "Thank you to everybody who's allowed me to make my music and allowed me to even be considered."
The singer, who was raised near Aberdeen, thanked her husband, Adam Gouragine, whom she married last summer.
The show opened with rock band Muse, who were backed by a 60-piece string section as they performed their track Supremacy.
Presenter James Corden made reference to last year's show in which he memorably cut off singer Adele as she collected her best album prize.
He pointed out that Swift had once been cut off mid-speech but there was no chance of such an occurrence tonight. "Not on my watch," he joked.
Mumford & Sons picked up the prize for best British group, two years after missing out on the prize when previously shortlisted.
It was the band's second Brit win, having collected the best album prize in 2011.
Frontman Marcus Mumford said: "Thanks very much indeed. We weren't expecting that. I don't think we've really taken the opportunity to thank people who have come to our gigs."
The best British breakthrough prize went to Ben Howard, who was last year nominated for the Mercury Music Prize.
Collecting the prize from Radio 1 breakfast show host Nick Grimshaw, Howard said his mum had called up her friends to ask them to vote for him.
CORDEN chatted to members of heartthrob boy band One Direction between performances and teased singer Harry Styles about his reputation for being drawn to older women.
"We've got Sharon Osbourne and Annie Lennox here tonight – who've you got your eve on?" Corden asked.
Robbie Williams, who has more Brits than anyone else after collecting 17 as a solo star and member of Take That, was also among performers as he sang his hit Candy.
Howard went on to collect his second prize of the night by taking the best male solo artist award, beating artists such as Olly Murs, Calvin Harris and Richard Hawley.
Critics' Choice winner Tom Odell was in the audience after picking up his award earlier in the year. "It's crazy to be here," he said.
The evening also featured a much-anticipated performance by Justin Timberlake, who is rejuvenating his musical career after a spell in which he devoted his time to acting. The US hunk, wearing a shiny elegant suit, showcased his new track Mirrors.
Lana Del Rey took the international female award, thanking her record label Polydor for its help in "turning my life into art".
Coldplay were declared best live act, beating Muse, Mumford & Sons and the Rolling Stones.
Only drummer Will Champion and guitarist Jonny Buckland from the quartet were at the event and Champion thanked their fans.
Adele collected the best single prize for her James Bond theme Skyfall – and joked about how she was cut off in her prime at last year's ceremony when the show began to overrun.
In a video acceptance, she said: "Hello everyone. I won't keep you too long because I don't want to interrupt the best album speech at the end of the night."
Taylor Swift performed her track I Knew You Were Trouble, wearing a long wedding-style gown, which she whipped off to reveal a black lace mini-dress.