Following in the footsteps of father Lawrence Kasdan, director Jake Kasdan has carved out a successful career alternating between movies and television, with a focus on comedy. He directed the “Freaks and Geeks” pilot and co-wrote and directed “Walk Hard: The Dewey Cox Story,” which earned him a Golden Globe nom.But it was this year’s R-rated laffer “Bad Teacher,” starring Cameron Diaz as a potty-mouthed, pot-smoking teacher, that put him over the top. Despite mixed reviews and its R rating, the film grossed $216 worldwide. “It was one of the funniest scripts I’d ever read, and while people kept telling me about the problems of doing an R-rated comedy, the challenges are the same as making any comedy,” he says. “You want it to be funny all the time and you don’t want to be seduced by the R rating.” Kasdan, who produced actress Jennifer Westfeldt’s directorial debut, “Friends With Kids,” which bowed at the Toronto Film Festival in September, also directed the pilot for the new hit series “The New Girl” (the first pickup of the season) at Fox, where he has an overall deal to write, produce and direct.