For years, putting feisty comic Kevin Hart across from any movie star would automatically light a fire underneath an otherwise middling comedy. He was the magic ingredient, the spice that would enliven anything. But recently, Hart has been usurped as the secret sauce in any comedy sandwich.

The challenger to his throne is “Girls Trip” breakout star Tiffany Haddish, and it was only a matter of time before the two faced off in a war of quippy comebacks. But in Malcolm D. Lee’s “Night School,” co-starring Hart and Haddish, Hart is the star who needs a wacky supporting cast to prop him up.

Hart characters have become a genre unto their own. He plays men with outsize personalities, hustlers and salesmen who punch above their weight class when it comes to love interests and have a tenuous relationship with the truth.

In a climatic speech in “Night School,” Hart’s character, Teddy, announces “I’m a liar. I’m a loudmouth hustler,” and it’s one of the most honest moments in his filmography.

Because we know Hart’s cinematic persona so well by now, what livens up “Night School” — aside from Haddish, who plays his supportive, yet shockingly violent teacher — is the band of weirdos that are his classmates.

Lee has assembled a group of beloved comic character actors to surround Hart and offer him some fodder off which to bounce. Rob Riggle, Al Madrigal, Mary Lynn Rajskub and Romany Malco embody a group of hilariously detailed characters that could easily carry their own spinoffs.

Malco is especially funny as the conspiracy theory-spouting Jalen, who fires off couplets about the Illuminati and robots so quickly no one knows what hit them.

The crew is what carries “Night School” through the bumpy patches.

The writing of Haddish’s character Carrie is particularly inconsistent — she’s at once sweet, self-sacrificing and caring, but she’s also incredibly tough, battering her night school students with retorts, insults, tough love and sometimes even her fists and feet. You can just never quite get a handle on who her character is.

Still, if any filmmakers have yet to consider Haddish for an action film, her powerful performance in the MMA ring with Hart is a worthy audition.

The film’s identity crisis may come from the six (six!) credited writers on the project. The pace and structure are incredibly strange, and the flailing romance between Teddy and his fiancée Lisa (Megalyn Echikunwoke) is formulaic and bland. Hart’s on-screen romances always have the same conflict — he’s immature — and by this iteration, it’s tired.

Thank goodness for Riggle, Malco, Madrigal and Rajskub, who bring enough weird energy, bizarre asides and just plain moxie to their characters. A lot of the humor plays fast and loose with ethnic and cultural stereotypes, and it isn’t always successful. But the night school classmates make the comedy work, and there are indeed some very funny moments.

That’s not to say Hart and Haddish don’t bring the laughs. They do, but it’s nothing surprising or fresh, and it seems like their characters weren’t exactly written, so much as room was left in the script for the two stand-ups to riff.

“Night School” makes the grade, but just barely. It still needs a little bit of remedial work.

“NIGHT SCHOOL”

** 1/2

(PG-13, 1:51)