The win made Edfors the first two-time winner this season on the European Tour. He claimed his first tour win in March at the TCL Classic.
'It feels great of course,' Edfors said. 'I told myself I was going to buy a car after my first win and I haven't done that yet. I guess I have to buy that car now. This was a fantastic win for me.'
Gary Emerson nearly made a huge comeback for the win. He fired 5-under 67 to end at 10-under-par 278 and shared second place with Jarmo Sandelin (70) and Stephen Gallacher (71).
Overnight leader Paul Casey had a two-stroke lead through eight holes Sunday, but things fell apart from there. He played holes nine through 11 at 4 over par and bogeyed two of the last three holes as well, to fall back to minus-9.
Casey shared fifth place with defending U.S. Open champion Michael Campbell, who also struggled to a 2-over 74. Paul Broadhurst was one stroke further back at 8-under-par 280 after a 4-under 68 at The Belfry.
Edfors bogeyed the par-4 first for the third time in four days to slip to minus-8. At the time, he was five strokes behind Casey. Edfors reclaimed that lost stroke with a birdie at the par-5 third.
The Swede birdied the par-3 seventh for the third consecutive day. That got him to 10 under, but he was still four behind Casey, who had birdied the fifth.
Edfors parred his next seven holes. The 30-year-old rammed home a birdie putt on the 15th to grab a one-stroke lead as Casey tumbled down the leaderboard.
Casey had bogeyed the ninth, double bogeyed No. 10 and bogeyed the 11th to fall back to minus-10.
Edfors birdied the par-5 17th to move to 12 under and two strokes clear of the field. He did three-putt for bogey from the right fringe at the last to fall back to minus-11.
'I didn't get off to a good start with that bogey there on one,' admitted Edfors. 'I didn't know until 13 that I was tied for the lead. I knew if I could take advantage of the par-5s I would have a good chance of getting it done. I made a great putt on 15 and another on 17.'
Casey dropped another stroke on the 16th to fall back to 9 under. He lipped out an eagle putt on 17 and settled for birdie. He had a chance to force a playoff with a birdie on 18, but he missed the green long and left and walked off with another bogey.
Campbell had gotten within one of Casey's lead with a birdie on No. 3. However, the New Zealander double bogeyed the ninth, then dropped shots on 12 and 14 as well.
The 37-year-old Campbell got those strokes back with birdies at 15 and 17, giving him a chance to force a playoff with a birdie at the last. He three-putted from the fringe on 18 for a closing bogey.
Sandelin and Gallacher played one group ahead of Edfors. Sandelin birdied three of the first five holes. He posted four bogeys and three birdies the rest of the way to post 10 under.
Gallacher carded his lone birdies at five and 13. He slipped to his only bogey on the ninth.
Emerson was four groups ahead of Edfors and was 1 under through four holes with two birdies and a bogey. From there, Edfors notched four birdies to share second at minus-10.
Tom Whitehouse, Jonathan Lomas and Graeme McDowell shared eighth place at 7-under-par 281. Oliver Wilson, Order of Merit leader David Howell and Darren Clarke were one stroke further back at minus-7.