John Cargill, from South Kirkby, was handed the sentence at Leeds Crown Court on Friday for two non-recent offences against the then child victim in the Pontefract area.
He will also be required to sign on the sex offenders register indefinitely.
Cargill came to police attention after officers were told in autumn 2016 that he had sexually assaulted the girl on an occasion between 2009 and 2010.
Detective Inspector Charlie Manson of Wakefield District Child Safeguarding said: “John Cargill committed some awful offences against his victim and we welcome his sentencing.
“His victim has shown real bravery through the court process and I wish to commend her courage in coming forwards.
“We hope seeing her attacker's crimes exposed in the public eye and seeing him jailed may be of some comfort to her and her family.
“I would reiterate that we would always encourage victims of non-recent sexual offences who may not have reported what happened to them to come forward.
“We will always listen and specialist detectives will investigate every report made.”