James Hunter, 38, met the girl three times and sent her naked photos of himself over the course of two months after exchanging messages on Snapchat, the social-media app.
Hunter and the girl drove to a secluded area near Scarborough on three separate occasions between November 2015 and January this year, when they kissed and engaged in sexual activity inside his car.
Prosecutor John Dunn said Hunter told the girl it was wrong because of his age and that he feared going to prison, but they continued to message each other every day.
Mr Dunn said Hunter ended the affair in February but the girl told her friend what had happened, and ultimately police were informed.
Hunter, of Tindall Street, was charged with two counts of sexual activity with a child and pleaded guilty to both offences. He appeared for sentence on Friday.
His barrister Taryn Turner said Hunter was “extremely remorseful” about his actions and the “pain and upset” he had caused the girl and her family.
“In many ways, he was a pillar of the community,” she added. “He had a good job where he was well thought of and had done charity work.”
.Judge Andrew Stubs QC said although he didn’t regard Hunter as a sexual predator, there was evidence of grooming.
“You cultivated (the girl), telling her you were the right age for her - nothing could be further from the truth,” added Mr Stubbs.
Hunter remained expressionless as Mr Stubbs handed down the four-year sentence.
The disgraced football coach was also placed on the sex-offenders’ register for life and subjected to a sexual-harm prevention order, which will run indefinitely and restrict his use of messaging services and contact with children.