William Russell, 25, set up the Teen Support Network, which promotes online safety for young people, in 2012.
But the District Court in Adelaide heard on Monday Russell never used the network to help children stay safe online, instead exploiting two 15-year-old boys on the Kik and Snapchat messaging apps.
Prosecutor Andrew Fowler-Walker said Russell exchanged nude photos with the boys and arranged meetings in order “to kiss and hug”, but the plans never eventuated.
He has also admitted possessing 51 child pornography images, which were found by police at his home.
Police began investigating Russell after an article promoting the Teen Support Network was published in 2017.
“He was not honest in that article when he said that he used the Teen Support Network to warn young children of the threat of online sexual predators,” Mr Fowler-Walker said.
“The investigating officer could find no evidence that he ever warned any youths about online sexual predators.”
Matthew Mead, for Russell, said his client was left with an intellectual disability after he suffered two strokes in utero, and was described by a forensic psychologist as a “naive and immature young man”.
Mr Mead said his client was “most ashamed and embarrassed” about his crimes, before he read out a letter of apology to the court.
“I have hurt a lot of people and I am extremely sorry,” the letter read.
“I will be a stronger, wiser person and work my utmost to be an upstanding leading member of the community, above and beyond what I have previously done.”
Russell was nominated for the Young South Australian of the Year in 2017 for his work as an “anti-bully crusader”.
He has pleaded guilty to charges including procuring a child for sexual activity and aggravated possessing child exploitation material.
Chief Judge Michael Evans continued Russell’s bail ahead of sentencing in November.