During a trip to LA in 2010, he came to the attention of actor and musician Jamie Foxx, who then gave him the run of his home and recording studio during his stay, and his online fan base continued to grow, even reaching Elton John.
Sheeran soon found a label that would sign him on his own terms and when The A-Team was officially released as a single in 2011, it entered the UK charts at No3 and went on to be the biggest-selling single there for 2011.
Three months later his debut album + entered at No1 and has gone on to sell more than two million copies world-wide.
Then came the Brit Awards, the Grammy nomination (he performed The A-Team at the ceremony as a duet with Elton John), and Britain's prestigious Ivor Novello songwriting award.
It all sounds like a bit of a fairy tale, really, but Sheeran's songs have clearly struck a chord with young fans, and his laid-back, everyman sort of style has found appeal in an age of elaborately constructed pop star personas.
His increasing popularity has him mixing with those stars (he's written songs for One Direction, including their No1 hit Little Things, and will be on tour with Taylor Swift from mid-March), but Sheeran's managed to keep away from squeaky clean, overly polished presentations - it's still just him, his voice, miniature guitar, and songs about everything from second chances, to the seduction of being drunk, to a drug-addicted prostitute he met at a homeless shelter.
Fortunately, he seems to enjoy the lifestyle of never-ending touring. "I don't think I could actually cope without it, funnily enough.
"I had two weeks off at Christmas, and I was just at a loss for what to do, so I kind of love being on tour, it gives me something to wake up for, in a funny way. And I'm seeing places in the world I never thought I'd visit."
He has actually bought a house back home in Britain, but he won't be living there for some time yet, as he plans to spend most of this year in the United States.
"But it's good, because buying a house is one thing, but filling a house is another.
"So I guess it gives me a bit more time, over the next year or so, to slowly fill it with lots of different chairs and casserole dishes and knives and forks. I have to make it liveable first."
One might think touring endlessly on your own could get a bit lonely, that maybe Sheeran would occasionally wish for a band to walk out on stage with, but he revels in the solo spotlight.
"I think when you're a musician you obviously have an ego when it comes to performance, because you need one. You need to be able to step out on stage and so that's my thing I guess - I like all the attention being on one person."
It makes it a little easier for him to write new songs while on tour, too - he's already got enough for another album, but we won't be hearing any new tracks during his show here next week.
"I'm actually going to keep all of them back until the last minute, I think, just because with the internet nowadays, it can take the excitement out of things if you play them early."
And he's keeping mum on further plans for 2013 as well - particularly whether he'll be writing any more songs for other artists, or embarking on any collaborations.
"There's a lot of things happening this year that people will see as they unfold, but I'm gonna wait and see how that all plays out."
Fans can be sure that Sheeran has no plans to have a break any time soon, despite having achieved at the young age of 21 what many might view as lifelong goals. "I think I have to have another album that's not only as well received by the fans, but that hopefully sells four or five times as many as this one" he explains.
"There's always more you can sell. Adele has sold something like 25 million world-wide, so until I'm up at her level, I shouldn't stop."
Who: Ed Sheeran
When and where: Playing Saturday, March 9, at Vector Arena
Listen to: + (2011)
-TimeOut
