Hamish Tait, 35, faces a staggering 329 total charges of child abuse between 2009 and 2025 while working at 62 centres.
Some 136 alleged victims are known to police and a further 22 are yet to be identified.
Morgan, 33, said the accused predator worked at the front desk at one of several centres where the Australian Federal Police said alleged abuse took place.
She told AAP the accusations had shocked parents.
"We didn't know - he was trusted by so many people," said the mother of two, who asked for her surname not to be used amid an ongoing court case.
The mother, who praised the staff and owners for their professionalism and high operating standards in the past year, said she was notified of Tait's arrest by the centre's management.
"When I was told I didn't sleep for days - it was traumatic," she said.
"I get so choked up talking about it because it's like every parent's worst nightmare come to life."
The 35-year-old alleged offender was arrested and charged in July 2025 under Operation Moonbi after police seized almost 2.5 million files from electronic devices at his home and has been in custody.
A non-publication order sought by the AFP to protect the integrity of the police investigation was lifted on Monday after a legal stoush.
"Parents in the centres knew but we also knew that there's a suppression order and that if your child was affected, AFP are going to contact you," the mother said.
She also noted Tait was not an educator on-site but was around the children as a staffer and had a professional camera for his social media duties.
The centres are owned by childcare provider Fit Kidz, which said it was "shocked, disgusted, saddened and sorry for the pain that has been caused".
"Our focus has always been and will continue to be supporting those affected and strengthening the safety of children entrusted to us," the centre said in a statement.
1800 RESPECT (1800 737 732)
National Sexual Abuse and Redress Support Service 1800 211 028
Lifeline 13 11 14
Kids Helpline 1800 55 1800 (for people aged 5 to 25)