The court heard how Clark made initial contact with his three teen victims, aged 13 and 14 years, via social media online platforms including Snapchat late last year.
Using the alias 'Jack Lewis', he portrayed himself as a 17-year-old male and enticed his victims to exchange various text conversations and shared various images of themselves.
Clark sent several photos to one victim, 13, via Snapchat which she saved on her phone. She also text him.
This victim sent nude pictures and video to Clark as he requested and in return, the defendant exchanged pictures of himself with his genitals exposed.
Clark then messaged the same victim about her having sex with his bogus older cousin for money.
After several further messages, Clark picked the victim up in his car outside a local school and drove her back to his home. The victim was wearing her school uniform.
The girl told Clark she was only 13 and had "never done this before".
She asked Clark for the money he promised and after being paid $100, they had sex twice. He also performed other indecencies on the victim.
Clark also enticed the two other girls, both aged 14, through his social media alias to meet him near their school before he drove them to a secluded bush area.
He then sexually molested both victims, paying one $50 and the other $20, before he drove them back to their school. Both girls were also wearing their school uniforms.
Crown prosecutor Duncan McWilliam read victim impact statements in which the father of one victim spoke about how their family's "world has crumbled" due to Clark's actions and "lots of psychological distress" had taken its toll on the whole family
Another parent said their whole family was left "totally devastated" and their daughter who once used to be a "confident, happy young woman" was not the same.
"You have ruined a young girl's life," the mother said.
Clark's offending led her daughter to self-harm and she had also made several suicide attempts, she said.
McWilliam argued a minimum non-parole period was needed to reflect the gravity of Clark's "predatory premeditated behaviour" and send a strong deterrent message.
For the youngest victim, there had also been the risk of pregnancy and catching a sexual disease from Clark, he said.
Clark tried to "minimise his offending" and also tried to hide a 2010 conviction for exposing himself to two 9-year-old girls, McWilliam said.
Clark's lawyer Rachael Adams argued that a minimum non-parole period was not required as her client's rehabilitation prospects were good and he was committed to that goal.
She urged the judge to also take into account Clark's expressed remorse and his growing insight into the impacts of his offending.
Judge Stephen Coyle said the victim impact statements clearly showed the significant traumatic impacts on the lives of the girls and their families.
Judge Coyle said he hoped that Clark had listened carefully to what he had done to them.
"For different reasons these [statements] were harrowing," he said.
Speaking directly to the families and friends of the three victims, Judge Coyle said no blame or guilt for what happened could ever be placed on these girls.
"They have done nothing wrong. The only person who should feel guilt is Mr Clark."
Judge Coyle said it was no credit to Clark that he was less than honest with a psychologist who provided two reports about him and to the pre-sentence report writer.
Only "ruthless honesty" would demonstrate Clark's true remorse, the judge said.
Judge Coyle sentenced Clark to four years and 11-months' prison and imposed a minimum non-parole period of two years and six months imprisonment.
The judge said a stern "deterrent message" was needed not just for Clark but also for the wider community.
