Chung had been the standout player of the tournament winning all of his matches en route to the final, including a dominant 4-0, 4-1, 4-3 (1) display against Rublev in the group stage.
A high-quality final full of sublime ball-striking was a fitting end to a promising debut for an event which has experimented with a range of innovations such as shorts sets, "sudden-death" deuces and on-court coaching.
One more point and he could force a tie-break, and from there a fifth set, but Medvedev could not save a third match point.
UAE condemns attack on Bahrain oil pipeline
The UAE on Saturday condemned the terrorist explosion and expressed its solidarity with the kingdom. . An oil pipeline exploded in Bahrain on Friday, causing a massive fire near a market and a hospital.
That was the turning point for the South Korean, who won the next two sets to seal the title in an hour and 57 minutes. The last Korean to win on the ATP tour was Lee Hyung-taik back in 2003.
Croatia's Borna Coric beat Daniil Medvedev 4-3 (7/5), 2-4, 4-1, 4-2 but will have to wait until Thursday to book his berth after a fightback by the Russian who saved two match points.
Whether or not any of the rule changes trialled this week ever become regular features remains to be seen, although the 25-second shot clock and shorter warm-ups were popular with players and fans alike.