Darren Shillito was found guilty of three counts of rape and one count of sexual assault on 12 July 2021 following a trial at Canterbury Crown Court.
The 40-year-old, formerly of Victoria Park, Dover, appeared before the same court on 24 September and was jailed for 18 years.
He will serve an extra year on licence at the end of that term and will be the subject of an indefinite Sexual Harm Prevention Order (SHPO).
In 2019, police were contacted by a relative of the victim, who said she suspected that the girl, who was of primary school age, had been sexually abused by Shillito.
Specialist officers investigated, speaking to the victim, analysing notes she had made and interviewing others who knew her.
Following these enquiries, Shillito was arrested at his home in November 2019 and was later charged.
Detective Sergeant Daniel Hall, of the Kent Police’s Vulnerability Investigation Team, said: ‘This was a very troubling case and I would like to praise the courage of the young victim and her family who have supported the investigation.
‘Shillito appears unrepentant about these serious crimes and his repeated denials have further worsened the ordeal his victim has been through.
‘I am pleased our investigation led to these guilty verdicts and the resulting sentence will see this dangerous man jailed for a considerable amount of time.
‘I urge anyone who is being sexually abused or suspects someone they know is being mistreated to contact police as soon as possible. We will safeguard anyone at risk and work to bring abusers before the courts.’