The amateur palaeontologist was out hiking with his father in a fossil-rich part of Alberta, Canada this July, when he saw bones protruding from a rock.
On Thursday, the skeleton's excavation was completed.
The boy, Nathan Hrushkin, says when he first laid eyes on the bones, he was "literally speechless".
"I wasn't even excited, even though I know I should have [been]," he tells the BBC.
"I was in so much shock that I had actually found a dinosaur discovery."