It is led by Deputy Chief Brenda Leigh Johnson , played by Kyra Sedgwick .
The cast consists largely of an ensemble of detectives who make up the LAPD 's fictional Major Crimes Division .
Major Crimes Division is led by Deputy Chief Brenda Leigh Johnson , played by Kyra Sedgwick .
The cast consists largely of an ensemble of detectives who make up the LAPD 's fictional Major Crimes Division .