Rizzo is a pretty stock character, the tough girl, and a darker alternative to the blond blandness of leading lady Olivia Newton-John as Sandy. The role gives Channing plenty of opportunity to show off her wit and comic timing (witness the gems tossed off as throwaway lines in the first scene with Patty Simcox at lunchtime), as well as a more mature sensibility (the scene with Jeff Conaway at the drive in). Channing convinces us that she's in command of not only her abilities as an actress, but as the definite leader of the Pink Ladies in her initial scene. There's no question that the pecking order in the club is "Rizzo first, then everyone else". That Rizzo comes off as more than just a stereotype is thanks to Channing. So, Channing is both an expert verbal comedienne, and then turns on a dime to bring off the more serious moments with Conaway.
She even gets a killer solo number in "There Are Worse Things I Could Do", where the character reveals what we've expected all along, that the 'tough girl' has feelings and can be hurt just as easy as anyone else. That is evidenced by the wry smile that Channing allows herself at the song's end. This smile had escaped my notice after numerous viewings of this film until it was pointed out to me by my friend Summer last night, and that smile, was the basis for this entire post. That moment in the film spoke to me, revealed Rizzo's honesty with herself (and the audience) that she is unable to share with any of the characters in the film, neither her boyfriend or closest girlfriends will ever see her this openly, vulnerabilities exposed.
Granted, Channing was (as was the whole cast) well past her teenage years when she tackled the part of Rizzo, and yet she yields to a youthfulness in her performance that is tangy and spicy (again, some flavor to make up for the plainness of Olivia's lead performance). It may be far from her most acclaimed performance on film (which was not too shabby at all in 1993's "Six Degrees of Separation"), and it will probably always be the role for which she is most remembered, and whether she appreciates it or not, Rizzo and "Grease" made me a Stockard Channing fan for life, even after "The Big Bus" and "The Fish That Saved Pittsburgh". Now, how many film fanatics can say that?