Lean on Me (1989)

In this fact-based film, a New Jersey superintendent, Dr. Frank Napier (Robert Guillaume), watches helplessly as East Side High becomes the lowest-ranked school in the state. With nowhere else to turn, Dr. Napier enlists maverick ex-teacher Joe Clark (Morgan Freeman) to take over as principal of the declining school. Unfortunately for Clark, before he can focus on improving the student body's state exam scores, he has to somehow rid the school of its gang and narcotics problems.