An "anti-bully crusader" and former Youth award finalist told a court he is sorry for grooming teenagers online as well as possessing child pornography.
William Russell, 25, was nominated for Young South Australian of the Year after he set up the Teen Support Network, promoting online safety in 2012.
But instead of using the network to help keep children safe online, he gained the trust of his victims and exploited two 15-year-old boys on social media apps Snapchat and Kik.
In court, prosecutor Andrew Fowler-Walker said Russell exchanged nude photos with the underage boys and had arranged to meet the pair so he could "kiss and hug" them, AAP reported.
But the plans never eventuated.
Police became suspicious of Russell when in an article about Teen Support Network he said he uses the site to warn youths of online sexual predators.
However, police found no evidence he ever warned users against sexual predator dangers.
After investigating Russell, police found 51 child pornography images at Russell's home.
Russell pleaded guilty to charges including procuring a child for sexual activity and aggravated possessing child exploitation material.
The 25-year-old's lawyer Matthew Mead said his client was "most ashamed and embarrassed" about his crimes before he read out an apology in court.
Russell is on bail until his sentencing in November.
He could face decades behind bars.