Father Michael Maher, 74, pounced on the girl when she was 12 and abused her in her own living room while her mother was in the house.
Maher was close friends with the schoolgirl’s parents and regularly called at their Lanarkshire home.
The offences started in 1968 when he was 25 and continued for four years but stopped when the girl was 15.
The victim kept the ordeal secret until she told her husband after Maher conducted mass for her parent’s wedding anniversary but didn’t contact police due to the ‘high regard’ they had for him.
However after her father died and her mother’s health failed she contacted him by email in 2016 and told him she hadn’t forgotten his attacks.
Maher, who was the parish priest for St Isidore’s, in Biggar, Lanarkshire, confessed his guilt and contacted church officials to resign.
Maher, of Stobo, Peeblesshire, appeared at Hamilton Sheriff Court and admitted lewd, indecent and libidinous behaviour against the girl between February 1968 and February 1972.
He has now been put behind bars by Sheriff Thomas Millar who labelled Maher’s conduct ‘abhorrent’.
Depute fiscal Morag McClintock told the court Maher molested his victim in her parent’s bedroom before lying on top of her and simulating sexual intercourse during visits to the family home.
Maher, who was ordained in 1968, also brought the girl to his parish house in Coatbridge, Lanarkshire, where he kissed her and also lay on top of her.
Miss McClintock said increased publicity over historic sexual abuse prompted the woman to contact Maher and led to his email confession.
She said: “The accused indicated he had always expected an email from the complainer and part of the email read, ‘I am so sorry for the hurt and pain I caused you, and still do, and all the harm done to you and to your family and I beg your forgiveness.’”
Miss McLintock said the 62-year-old had been left damaged by her torment.
She added: “She attributed the failure of relationships and her first marriage to the abuse.
“She never got over the abuse and blamed it for ruining her childhood.
“She felt she was thrown into an adult life when she was too young and as a result did not understand the sexual and emotional feelings.”
Lene Doherty, defending, said: “He is 74 and the offending behaviour took place some years ago and he has no previous convictions and has never come to the attention of the police until this case.
“After this offending came to light, a thorough investigation was carried out and no further matters came to light.
“He stood down as parish priest after being arrested and charged and since standing down he has had to move three times and now stays in an isolated cottage in the grounds of an estate owned by an acquaintance.
“No blame is attributed to anyone but to him himself and he is ashamed and embarrassed and accepts full responsibility for his actions.
“Since the offending behaviour he has shown dedication to parishioners and his role within the community.”
Sentencing Maher, Sheriff Millar told him: “The sexual abuse of children is abhorrent.
“The girl placed a trust in you and her parents placed trust in you. That trust was abused by you.
“The natures of the offence and the breach of trust lead me to believe that a custodial sentence is the only one that can be imposed on you.”
A spokesman for the Diocese of Motherwell said: “In September 2017 Police Scotland informed the diocese of an investigation into a historical allegation made against Fr Michael Maher, parish priest of St Isidore’s Biggar and St Mary Magdalene’s Forth.
“Fr Maher stood down from parish ministry immediately while the necessary police investigations were conducted. This has now been followed by court proceedings in which Fr Maher has pled guilty.
“The Diocese of Motherwell will extend whatever help it can to all those involved.”