He volunteered to work at a Huddersfield school and dreamed of being a teacher.
But pervert James Sweeting is now behind bars after a court heard of his sex crimes against young girls.
He has been jailed for a total of four and a half years.
Sweeting touched a 15-year-old girl indecently when he got her alone on one occasion.
Leeds Crown Court heard he also requested another older girl to send pictures to him of her in her underwear and said he wanted to kiss her and told her to wear sexy underwear for school.
Sweeting, who had hopes of being a teacher, also exchanged explicit images with another girl in America although he knew she was only 13 and performed a sexual act so she could watch him on screen.
Sweeting, 23 of Bedale Drive, Skelmanthorpe, admitted the sexual assault, causing or inciting a child to engage in sexual activity, and engaging in sexual activity in the presence of a child.
He was ordered to register as a sex offender indefinitely and barred from working with children.
Sentencing him Judge Geoffrey Marson QC said it was a tragedy to see a man of his intelligence and calibre in the dock on such offences. “You have thrown away forever any prospect of teaching.”
He accepted Sweeting had not volunteered at the school with a view to offending against pupils but he had then abused the great trust placed in him.
There was an element of grooming in the cases involving the 17 year old girl and the 13 year old as he developed his contact with them on the internet.
While the girl involved in the assault had suffered psychologically as a result of what he had done to her.
“They are in no way to blame, the blame lies wholly at your door.”
Ian Brook prosecuting said Sweeting had sat next to the girl who he assaulted at school and initially moved his hand up and down her knee over her trousers. He put her hand on his trousers but she pulled it away.
She did not know what to do but later he was alone with her and this time kissed her and put his hand inside her trousers but removed it when somebody walked by.
When arrested and suspended from the school he denied the offences saying he was a Christian and did not believe in sex before marriage. He said he had swapped photographs with women on the internet but they were adults.
Michael Brady representing Sweeting said he was a sexually inexperienced young man who had found himself in a situation where he was not much older than the girls at the school in a voluntary role “it was easy for lines to become blurred.”