The world number two triumphed 6-3, 6-3, 3-6, 6-3 and will face either top seed and eight-time champion Rafael Nadal, who beat him in the 2012 final, or Britain's Andy Murray for the title.
Victory on Sunday would make Djokovic only the eighth man in history to complete the career Grand Slam.
"I played really well in the first two sets with great concentration, but the hot conditions were very tough for both of us," said six-time major winner Djokovic.
Playing in his 22nd semi-final at a major compared to a debut appearance for Gulbis, the Serb was hardly troubled in the first two sets on a sweltering afternoon in the French capital.
But Gulbis, the 18th seed who defeated 17-time major winner Roger Federer and sixth seed Tomas Berdych to get to his first Grand Slam semi-final, rallied in the third to briefly breathe life into the contest.
In the end, however, Gulbis's 44 unforced errors to Djokovic's 25, as well as his ability to convert just two of his seven break points proved crucial.
The crucial point summed up the 41-minute set as the Serb illustrated why he is regarded as the game's best returner, his early backhand putting Gulbis on the back foot and off balance with the Latvian unable to regain his poise.
Gulbis fired twice as many unforced errors in the opener, the heat and bright conditions making the ball fly.
Watched by a host of former champions including Bjorn Borg and Gustavo Kuerten, Gulbis hit a lazy backhand long and was broken to trail 3-4 in the second set.
