Roger Ashcroft, 35, targeted the girl on multiple occasions at two addresses in Nottinghamshire and South Yorkshire.
His offending was exposed when his victim revealed the abuse to a teacher at her school.
Ashcroft was arrested by Nottinghamshire Police and was later charged with multiple offences.
During his police interviews he denied all knowledge of the offences but was later found guilty by a jury at Nottingham Crown Court of six counts of sexually assaulting a girl under the age of 13 by touching.
Ashcroft, of Hereford Road, Doncaster, appeared at Nottingham Crown Court yesterday (Monday) and was sentenced to six years in prison.
He was also made the subject of a sexual harm prevention order that will prevent him entering the same household as or having any undue contact with a girl under the age of 18.
He will also remain on the sex offenders’ register for life.
Detective Sergeant Mark Kimberley, of Nottinghamshire Police, said: “Ashcroft was responsible for an appalling catalogue of sexual abuse over a period of more than six years.
“But for the bravery of his victim in coming forward and asking for help his offending may well have gone undiscovered and unpunished.
“This kind of abuse can have a life-long impact on victims who, quite understandably, can struggle to come to terms with what has happened to them. I am pleased that Ashcroft has now been punished for these offences and that his future behaviour will be closely monitored once he leaves prison.
“This case is also a reminder of what we can achieve when victims find the courage to come forward and tell us what has happened to them in the past. We will listen to them, we will investigate and will do our utmost to get justice for them.”