At 5' 7½", Jack Black is even dumpier than Ferrell but no less creative in defying his bulk. In addition, he has eyes that, at times, seem to be unscrewing themselves from their sockets and eyebrows so expressive he can practically spell his name with them. (I always remember Black's eyes as being bigger than they are.) Ferrell and Heder come across as total fools, but I have known a lot of women who would find Black attractive. So when he does similarly foolish stuff, such as emphatic rock 'n' roll gestures to show what a large, uncageable spirit he is, it inevitably has some of the spazzy but gentle drama of the Harold Lloyd juvenile doing his jig and handshake to make friends in The Freshman, because you expect he could grow out of being that kind of fool.

This might work straight if Black didn't push it; unfortunately, his previous starring roles have required him to do just that. The title of Shallow Hal indicates the problem with that movie: sniffy feminist piety undermines the very scurrility the movie exploits for entertainment. (The title clucks its tongue and the movie can be explained only as an act of penance by the Farrelly Brothers.) The School of Rock was marginally more sophisticated in that we were clearly meant to laugh at the rants of Black's grade school teacher – both because of the content in itself and the inappropriateness of directing them at grade-school children. Ultimately, however, his "radicalism" helps build his students' self-esteem and the movie becomes drearily uplifting.

In Nacho Libre, the deadpan goofiness of director Jared Hess brings out the best in Black. Instead of being cast as a gleam-eyed, self-centered adolescent who becomes "human," as in Shallow Hal and The School of Rock, Black's Ignacio, a friar who is the male Cinderella in a Mexican monastic orphanage, is absurdly soulful from the start. He wants to do his best for the orphans, but can only serve them inedible slop because the monks don't give him enough money for fresh ingredients. He's a committed man of God but has doubts about his vows when the beautiful Sister Encarnación (Ana de la Reguera) joins the monastery.

Ignacio also harbors a secret passion for lucha libre, a Mexican form of championship wrestling, which he goes into on the sly to earn grocery money for the orphans. Sadly, Encarnación thinks wrestling is evil, and Ignacio and his tag-team partner, Esqueleto (Héctor Jiménez), aren't very talented, anyway. Not even God appears to be on Ignacio's side when he loses his shot at a championship bout against the title-holding meanie (a Keystone bully who humiliates him in front of the orphans when he asks for an autograph for them). So Ignacio withdraws for a spiritual retreat into the desert, across the street from Esqueleto's neighborhood.

In other words, the sincerity works in Nacho Libre because it's inseparable from the irony. Ignacio is so darn virtuous it has to be parody, and Black and the moviemakers use every opportunity to synthesize unintentional camp. In his other vehicles, Black has mixed comedy star strutting and straight acting in a way I found effortful. (In this respect, Mickey Rooney would be the mark Black fell short of.) Counterintuitively, the hermetic seal on Nacho Libre lightens Black's style. He gets laughs by speaking in a corny movie-Mexican accent, "casually" flexing his glutes to impress Encarnación, breaking out in a "jazzy" styling of the song he's written about her, and moves on to the next gag without overkill. (Hess, who is as good as anyone now working in comedy at varying the speed, always makes the pace serve the jokes and makes everyone look as good as possible.)