Detective Chief Superintendent Charlie "SuperMac" Mackintosh (Roger Allam) is Gene Hunt's superior. His first appearance is in episode 2.1. He knew details of murdered PC Sean Ervine who was apparently drawn in by Soho's many strip clubs. It was eventually revealed that Mackintosh was having an affair with Ervine's wife, Ruth.
When DI Drake theorises that the initials SM in Ervine's hidden diary indicate a meeting with Mac, she breaks into his office to see if a corresponding entry is also in Mac's diary. Mac had erased the entry, but Alex is able to easily raise the impression with a pencil rub.
Gene initially idolises Mackintosh who is one of the few people in the world Gene respects. At first he appears to be a benevolent character but it soon becomes clear that he is utterly corrupt and greedy. Mackintosh takes bribes but is careful not to spend the money overtly. Rather, he saves for his retirement by investing in art and property through a cover corporation run by the murderer and rapist Ralph Jarvis, who was Mackintosh's classmate in police training and whom Mackintosh cleared of murder in 1977.
He sees Gene as a protégé and eventually compels him to join the Masonic lodge that he and Ray Carling belong to. It is ultimately revealed that Gene has grown to distrust Mackintosh, considering him "bent as a ten bob bit" and he only joined the Masons in order to unravel Mackintosh's plans. Furthermore he holds the Masons in disdain and is "sick to his stomach" to have joined them, having seen their corrupt methods. Mackintosh has let various criminals loose on the streets on account of them being Masons, something which Gene disapproves of.
Mackintosh holds Alex in contempt but views her as a threat. He twice tells Hunt that Drake is 'poisoning' the team. When Hunt refuses to silence Drake, Mackintosh frames her for corruption and suspends her, pending criminal prosecution.
Having sworn to bring down SuperMac as his corruption becomes more apparent to Gene and Alex, Gene finally asks SuperMac if he can live with himself. SuperMac draws his sidearm and kills his accomplice who was about to walk free and aims at his own head. Even after Gene's intervention, he manages to shoot himself fatally, albeit in the chest. His last words are a warning to Gene of an oncoming threat called "Operation Rose".