Pearson befriended a single mother in 2015 and was introduced to her 9-year-old son, the court heard at sentencing.
He became so trusted that the child would stay with him after school and occasionally overnight.
Pearson also gained access to a 10-year-old boy and 13-year-old girl after cultivating a relationship with their parents.
The court heard how he invented a game through which he and the children would all end up naked in bed.
His offending only became apparent when explicit text messages were uncovered by one of the victim's mothers on her child's phone.
Police raided Pearson's home and discovered 130 objectionable electronic files, which included footage of a young boy using Pearson's bathroom, four males using a Dunedin public toilet, and people in the changing rooms of Moana Pool.
The Parole Board noted the man had similar convictions from 1999 and Corrections was now considering an application to place him under an extended supervision order.
Such an order is only imposed by the court for high-risk sex and violent offenders and can keep them under the spotlight for up to 10 years.
Pearson, who completed specialist sex-offender therapy last year, said he had a new perspective on his behaviour.
"The main learnings from the programmes he said were that help is out there, communication is essential with his support people and he was responsible for the choices he made," panel convener Serena Bailey said.
Pearson accepted he was an alcoholic and would have to avoid temptation while on parole.
Among the conditions imposed by the board were:
• To live at an address approved by Probation and comply with tenancy agreement
• Not to enter Otago
• Not to loiter near any school, early childhood education centre, park, library, swimming pool, other recreational facility, church or area defined by Probation
• Submit to electronic monitoring
• Abide by a 10pm-6am curfew
• Attend any counselling as directed
• Obtain Probation consent when starting or changing employment
• Not contact any victim of offending
• Not associate with any under-16s.
• Not to possess alcohol or non-prescription drugs.
• Disclose to Probation the details of any intimate relationship.
• Make any electronic device available for analysis.