The 43-year-old was a sports coach and employed as a teacher aide for a local school in Dannevirke, but was not a fulltime registered teacher.
The DIA said there is no evidence Johnson searched for material while on school property or using school equipment, or that his online activities escalated to physical offending.
The DIA, Oranga Tamariki and Ministry of Education are working in collaboration with the school to ensure that the necessary information and support services are available to the community.
DIA digital child exploitation team manager Tim Houston said people who think they're safe viewing or distributing objectionable material on the internet in the confines of their own home should "think again".
"There is public interest in holding offenders to account, to protect the community and deter others from engaging in similar crimes," he said.
"People who download this material feed a market that results in crimes being committed against young children."
The sentencing is a result of an investigation by the Department of Internal Affairs with support from New Zealand Police and New Zealand Customs Service.
Since being alerted by DIA, the school has been co-operative throughout the process and was quick to take appropriate steps once advised of Johnson's online activity, according to the DIA.
Houston reinforced the importance of a multi-agency approach to keeping children safe.
"DIA, police and customs work tirelessly together to investigate individuals trading in child sexual exploitation material," he said.
"Stopping the distribution of this type of material is critical because every time this material is shared, the children who are being exploited in this crime are re‐victimised.
"DIA will continue to work with our national partners to help keep the most vulnerable in our community safe."
