The 50-year-old was arrested at the prison on Tuesday morning.
A quantity of cash and drugs were seized in a joint operation carried out by the PSNI and the Prison Service.
Three properties were searched in Newtownabbey, Belfast and Kinallen, County Down.
The prison officer was questioned in relation to conveyancing prohibited articles into a prison, misconduct in public office, possession of criminal property and being concerned in the supply of Class A drugs.
A 28-year-old man and a 26-year-old woman were arrested in Newtownabbey.
A 55-year-old woman was arrested in Belfast and a 50-year-old woman was arrested in Kinallen.
They were all released on bail pending further enquires late on Tuesday night.
The PSNI's Head of Reactive and Organised Crime Chief Superintendent Tim Mairs said: "Detectives today seized Â£10,000 cash, a quantity of suspected Class A and Class B controlled drugs and a number of mobile phones.
"This operation is a good example of how collaborative working can disrupt crime and also demonstrates our commitment to Keeping People Safe by removing harmful drugs from society."
The head of the Prison Service, Ronnie Armour, said: "I welcome the result of today's joint operation with the PSNI and would take this opportunity to reiterate the zero tolerance drugs policy which operates within Northern Ireland's prisons."
A serving prison officer was among five people arrested as part of an investigation into trafficking banned items into Maghaberry Prison.