One for Arthur, trained by Milnathort-based Lucinda Russell, becomes the first Scottish owned horse to win since 1979 when Rubstic succeeded.
Derek Fox rode excellently as he came from the field to win by several lengths in the most famous steeplechase race in the world.
The 14-1 shot saw off the other 39 runners and riders having been one of the dark-horses for the race having finished strongly in the Becher Chase in December before winning comfortably at Warwick.
Cause of Causes came second, followed by Saint Are, Blaklion and Gas Line Boy.
Despite jumping into Blaklion at the second-last fence, the horse was spring-heeled at the final obstacle of the extended four-and-a-quarter-mile test.
Responding to everything asked of him by Fox, the runner galloped on resolutely to keep Cause Of Causes at bay and clinch success and go into the record books.
Fox, who only returned to action from injury earlier in the week, said: “It’s unbelievable. I can’t believe it. He just jumped so well, even though he was a long way back. He never missed a fence, within reason. He was unbelievable.
“I was lucky to get back in time - I want to thank Jack Berry House. Without them I wouldn’t have got back in time and I wouldn’t have been as fit as I am.”
An emotional Russell paid tribute to her Arlary Stable for the work they have done with One for Arthur who is owned by fellow Scots Belinda McClung and Deborah Thomson.
“I’m just so delighted,” she told ITV. “What a day. We’ve got a fantastic team behind us and I’m just so pleased for them.
“He’s amazing, he’s just improved every time. We kept thinking, barring accidents he’ll win the national, he just has.
“It’s brilliant for Scotland but really it’s for the whole team at the yard. They’ve worked so hard for this and to have are horse like him is just out of this world.”
McClung and Thomson, who own One for Arthur under the name Two Golf Widows,were left in disbelief after watching their horse triumph by four and a half lengths.
Thomson said: “I just can’t believe it. It’s been an absolutely amazing day. Arthur just cruised that race, Derek rode so well and I’m just a bit lost for words really.
“I just can’t believe we’ve won the Grand National - it’s fantastic.
“He’s given us a fantastic journey.”
McClung added: “I thought this morning, it’s baking hot so there’s no pressure now, he’s not going to win on that ground but I have to say he’s just shown his class today.
“He’s amazing and he got a great ride.”
All 40 horses returned to their stables in fine condition.