Edmund had never made it past the third round of a Grand Slam tournament before this year, but he is now just two wins away from pulling off one of the most unlikely triumphs in recent memory courtesy of a 6-4 3-6 6-3 6-4 win over Dimitrov.
The 23-year-old Briton made a perfect start with a break in the very first game, and with the exception of a spell at the start of the second set he never allowed Dimitrov to take control of the contest.
Edmund, who does not even have an ATP final appearance to his name so far in his career, went on to take advantage of regular Dimitrov unforced errors while also imposing himself on his more-experienced opponent.
Hawkeye eventually confirmed that a shot from Dimitrov on match point had gone long, sealing Edmund's place in the last four in Melbourne.
Only five British men have reached the semi-finals of a Grand Slam in the Open Era before Edmund, with the youngster joining Andy Murray, Greg Rusedski, John Lloyd, Roger Taylor and Tim Henman in that exclusive list.