Ackerman was a slightly effeminate, yet unbalanced, man who liked to think of himself as being extremely nice and friendly but was actually a brutal and sadistic bully. He claimed to have joined the Space Corps so that he could share his "sunny disposition" with people who did not have his start in life and insisted that "Nicey" was his nickname ("Pete, Part One").
At some point in his past, Ackerman had lost an eye and wore a prosthetic replacement. He walked with a slightly effeminate gait and often talked in a slightly camp fashion, but was prone to sudden losses of temper and acts of extreme violence.
He was in command of The Tank and, by extension, The Canaries. He was first mentioned by Lister as "That weird geezer with the one eye and the funny tick" ("Back in the Red, Part Three"). On the Dwarfers first day in The Tank, he and Knot assaulted the Cat for speaking out of turn.
When Dave Lister signed the Dwarfers up for The Canaries, Rimmer tried to weasel his way out by leading his friends in a singsong, claiming that they had entered the wrong hobby room. Ackerman made it clear that Rimmer had to "start acting like a man", something that Rimmer found difficult to imagine ("Cassandra").
Ackerman was later mugged by one of The Canaries and had his glass eye stolen. He had a date planned for the weekend and needed the eye back because his lady friend, Patricia, thought his eyes were his loveliest feature. Without the prosthetic, he insisted loudly "I'M ONLY HALF LOVELY". He threatened to suspend all Canary privileges unless someone returned the eye or informed him who had it. Rimmer was quite happy to inform on the guilty man to help Lister's appeal, an act that got him a good beating from the other prisoners.
Kryten later tricked Lister into trashing Ackerman's quarters, so that his date would be a failure, but Lister and Rimmer managed to put everything back right just in time for Ackerman's return ("Krytie TV").
Lister and Rimmer disliked Ackerman so much that they played an elaborate prank on him, inserting a capsule of truth serum (Sodium Pentothal) into his asthma inhaler. The truth serum caused him to admit to the bridge crew that he was late for work because he had been having "jiggy-jiggy" with the wife of the Science Officer whilst wearing his Batman Outfit. As punishment for their prank, Captain Hollister made the Dwarfers play a basketball game against Ackerman and his guards, assuming that they would be defeated by the brutality of the prison officers. Lister and Rimmer had other ideas, managing to dose the guards drinks with Boing, a virility enhancement drug that caused the guards to play the second half of the game with enormous erections that slowed them down to a crawl. This allowed the Dwarfers to dominate the game and win ("Pete, Part One").
Ackerman later performed an inspection on Lister and Rimmer's cell, finding a large quantity of illegal hooch and two very drunk prisoners. Both of them insisted that they were sober, a claim that Ackerman was able to disprove by asking "Who fancies a kebab?", to which both Rimmer and Lister replied positively. He had them taken to the prison hospital for a super-suck stomach pump.
Behind the scenes
Ackerman's violent nature was described in the script, but his camp nature and mincing walk were invented by Graham McTavish in rehearsals. He also came up with a lot of unofficial backstory for Ackerman, revealing in the DVD documentary "The Tank" that Ackerman had a strict upbringing, a wardrobe filled with strange uniforms and a sizeable arsenal.
Ackerman's rank was never stated, but he is described as being quite senior, with the insignia on his collar showing a high officer rank.
An interview on the official Red Dwarf website suggested that Ackerman, warden of The Tank on Red Dwarf, used to work at Justice World, alongside Barbara Bellini, whom he was having an affair with and had to leave in a hurry when caught out. Ackerman was the one who accidentally set the simulants free; providing an interesting irony that he later imprisoned those who helped contain one of those he had set free.