The in-form Chardy had won 12 of his previous 13 matches but the Frenchman was still left without a win — or even a set — against Djokovic after their 11th career meeting.
Chardy's best chance to end the streak came when the first set went to a tiebreaker, but a couple of loose shots allowed Djokovic to take control
The Serb, who has struggled this season after missing the second half of 2017 with an elbow injury, upped his level in the second set to force break points in three consecutive Chardy service games.
The Frenchman resolutely denied Djokovic at 2-2 and 3-3 before the three-time Wimbledon champion finally broke through with some of his best groundstrokes of the match to take a 5-4 lead.
"So for the first part of the match I was not really confident to actually hit the return," Djokovic said. "I was more kind of like chipping and trying to get it back in play, but it wasn't enough."
"From 3-3 in the second, I started to hit better and a couple of big returns when I broke his serve, so that's when I kind of found my rhythm and the footing and to adjust."
Cilic booked his place in a second successive Queen's Club final by edging Nick Kyrgios 7-6 (3), 7-6 (4).
The top seed raised his game when it mattered most, winning both tiebreakers against the Australian in a match which featured no breaks of serve.
Cilic, who was the runner-up at Wimbledon last year and at the Australian Open this season, will be playing his fourth Queen's Club final. He won the Wimbledon warm-up event in 2012 but has since lost finals in 2013 and 2017.
Despite the Croat's grass-court prowess and superior recent Grand Slam form, the fact that he's down 14-1 against Djokovic on head to head ensures Cilic won't be feeling superior.
"I watched here and there some of his matches," Cilic said. "He's playing well. He's starting to play better.
"You can see that he's fighting hard on the court, not letting any points go by him. You can see that mentality is back."
- AP