Jason Lineker, 34, of Mouslecoomb Way, Brighton, had been found guilty by a unanimous jury verdict at Lewes Crown Court on 27 August after a five-day trial which included evidence from witnesses and the girl herself.
On Friday 3 September he was sentenced to four and a half years plus one year on an additional prison licence.
He will be a registered sex offender for life, and was also given a Sexual Harm Prevention Order (SHPO) to last until further court order, severely restricting his access to children.
This was a re-trial after a previous jury had failed to agree on a verdict in November last year.
Detective Constable Angela Harvey of the Brighton Safeguarding Investigations Unit said: “The victim, a young child, was very brave, having to give evidence in two trials as a result of the hung jury outcome in November 2020”