George Shaw, from Hoyland, admitted a series of offences which took place between 1965 and 1975.
He was jailed for six years and two months for two counts of indecent assault on a girl under the age of 14.
Shaw was also ordered to sign the sex offenders’ register for the rest of his life.
Detective Sergeant Sam Newton said: “It’s hard to describe the impact an offence like this can have on a person.
“Shaw evaded justice for decades and I am pleased he is finally being held accountable for his horrendous actions.
“I would like to applaud the bravery shown by the survivor in this case - their determination to support this investigation was motivated by the hope it would inspire others to do the same.
“Many people wrongly believe it is too late to report a sexual offence if it happened outside of the forensic window.
“I would urge anyone who has suffered abuse to come forward as we can work together to bring those responsible to justice.”
The victim - who will remain anonymous - praised South Yorkshire Police for securing the conviction despite the case being blighted by delays due to Shaw’s age having been charged in 2019.
Speaking on the sentencing, the victim, who will remain anonymous for legal reasons, said: “I can’t put into words the toll that man had on me.
“My mental health has suffered for years as a result and I felt hopeless as he had got away with it for so long.
“I am truly grateful for the support I have received from South Yorkshire Police.
“If you are reading this and have also suffered a sexual offence, you are not alone.
“Reporting is not an easy decision but there are specially trained officers to support you throughout the process.”