Police accused seven people of drug supply at the event, including the 17-year-old Castle Hill boy with 579 capsules and $2075.
He's due to face a children's court on February 20.
Another alleged supplier, aged 25, was allegedly found with 100 MDMA capsules and a knife while a South Australian woman allegedly had 48 ecstasy capsules on her.
A further 16 people are due to face court for drug possession while 30 people were ejected for intoxication.
The HTID festival was one of two Australia Day music festivals in Sydney to have extra high-level critical care medical teams and more harm reduction measures, such as roving drug educators and free electrolyte drinks.
Five people were taken to hospital from Electric Gardens in Centennial Park due to suspected drug use, while 55 people were charged with drug possession and one woman accused of MDMA supply.
NSW Premier Gladys Berejiklian, whose government footed the bill for the extra protection, said she hoped and prayed people were starting to get the message to not take illicit drugs.
"I know some people are advocating one solution or another but there isn't one solution," she told reporters on Sunday.
"It's a complex issue.
"We want young people to feel they can have a conversation, we want young people to get help when they need it."
The premier and health department thanked staff and volunteers at the two festivals for ensuring attendees' safety.
"The additional critical care staff contributed significantly to the positive outcomes seen overnight," a NSW Health spokeswoman said.
Emergency Services Minister Troy Grant said there was no doubt the police force's disruption of three large drug operations in the lead up to the festivals had an impact in the quantity of drugs in and around these festivals.
Extra safety measures will also be in place at hip-hop festival Rolling Loud at Sydney Showgrounds on Sunday.