Ebony Thompson, aged 22 months, died after her neck became stuck on the fence at a daycare southeast of Darwin in 2023.
Childcare worker Casandra Lee Harris and the Humpty Doo Community and Child Care Centre pleaded guilty to failing to protect children from harm and hazards and inadequately supervising children.
Ebony's parents Floyd and Jade Thompson arrived at Darwin Local Court on Monday backed by supporters wearing purple, the toddler's favourite colour.
Judge Stephen Geary told the court it was the first time such prosecutions had come before a Northern Territory court.
The centre and its staff had, following safety inspectors' reports, missed an opportunity to fix the blind spot and ensure walk-throughs to pick up any children in the area, Judge Geary said.
This meant Ebony, completely unsupervised, was not found to be missing until it was too late.
The culpability of Harris was less than that of the centre and she was a very caring childcare supervisor who would have to live with her role in the loss of Ebony for the rest of her life, the judge said.
He read from the parents' impact statement saying Ebony was "the most amazing little girl you could ever imagine".
"She was a combination of everyone's greatest qualities. She was kind, full of light and love ... and walked this earth with such easy care," her parents wrote.
Following the sentencing, the Thompsons hugged each other in the public gallery, backed by their purple-clad supporters.
A childcare worker found Ebony trapped on the fence, upright and blue in the face, the court previously heard.
She was rushed to hospital but died two days later.
Judge Geary imposed a fine of $40,000 on the company and $2000 on Harris.
Ebony's family has called for a ban on loop-top fencing under a proposed "Ebony's Law" and wants a three-strikes rule for supervision breaches that would temporarily close childcare centres pending safety rectifications.
Two charges against another childcare worker at the centre, Gurmeet Kaur Rimpy, were dropped on October 1.
The centre's director, Rachel Lee Marsh, is understood to be contesting charges laid against her, to be heard at a later date.
