Barry Thrower, 37, assaulted the girl, who was under the age of 13, in Huntingdon during October 2022.
He also persuaded her to take part in sexual activity and, when the abuse was over, made her “pinky promise” not to tell anyone.
However, the following day, the girl confided in someone close to her who then called the police.
Thrower, of King Street, Desborough, near Kettering, was arrested but in police interview denied the offences.
He stood trial at Peterborough Crown Court in May, where jurors took just over three hours to find him guilty on two counts of assaulting a girl under 13 by touching and two counts of causing a girl under 13 to engage in sexual activity.
Thrower was sentenced at the same court on Friday (13 September) where he was handed a total of six years behind bars.
He was also placed on the Sex Offenders Register indefinitely and handed a SHPO to run until further notice, which will monitor any future offending.
Detective Constable Les Ellmer, who investigated, said: “Thrower’s sexual abuse had a huge impact on his victim, and I hope she can move forward and is now able to find some closure from this traumatic period of her life.
“Regardless of when it happened, we will always take reports of sexual offences, including child sex abuse, very seriously.
“Protecting young people from harm is one of our top priorities and we have specially trained officers who are there to support victims and bring offenders to justice.”
Anyone who is concerned someone may have been convicted of a sex offence, and could be posing a risk to a child, can apply for disclosure information through Sarah’s Law.
Did you know? Anyone who looks out for the welfare of a child can make an enquiry. This can include parents, carers, guardians, extended family, friends and neighbours.