Jeremy Dowling, 78, carried out the assaults on a 10 year old he met in 1973 at St Michaels Church at Budehaven, Truro Crown Court heard.
He was found guilty of six counts of indecent assault on a child.
Dowling is already serving a seven-year sentence for previous offences against boys at a private school.
The sentences will run consecutively.
The victim, now in his 50s, said he went to the police after reading of Dowling's abuse at the school where he worked as a teacher in the 1960s.
Dowling carried out the assaults on the boy in the 1970s at his farmhouse, in a church and on car journeys he took with the boy.
The abuse continued for four years when the victim said Dowling "took him under his wing".
Judge Simon Carr said his victim "had attended the church for guidance and help and what he found was you".
He said: "You enjoyed the risk of being able to control someone to that extent."
The Bishop of Truro, the Right Reverend Tim Thornton, said the case "fills me with sadness and shame".
He apologised "unreservedly" to the survivor of the abuse.
He said: "I am deeply sorry that Jeremy Dowling used a cloak of ecclesiastical respectability to gain trust and access; the church failed in its responsibility when it should have been there as a positive influence.
"I hope the fact that Jeremy Dowling has been convicted of these offences and will now be subject to a further prison sentence will at least bring some sense of justice."
Two counts of gross indecency against Dowling were dismissed.
Det Con Grant Mills of Devon and Cornwall Police said after the case that "even with historical offences, we can still bring offenders to justice".
"We welcome the sentence and hope it will help to give some closure to the victim," he said.
A former lay preacher has been jailed for eight years for indecently assaulting a boy he met through the church.