In recent weeks, two students at John McDonogh High School have been arrested for beating a security guard and another was arrested for hitting a teacher. Cosby's visit was arranged by the New Orleans NAACP, the New Orleans Times-Picayune reported.
Speaking to juniors and seniors, Cosby told them they would need to learn proper English to get into the working world. He also criticized the language frequently used in popular music.
Cosby addressed the suggestion that police target young black men and politicians build prisons for them.
"Let them build all the damn jails they want," Cosby said. "Make fools out of people that are building things for you that are not good."
Principal Donald Jackson said he has other plans to improve the school. He has invited the candidates for the local congressional district seat to teach 10th-grade civics classes on what congressional representatives can do to make schools better.