The assaults happened when Jeremy Dowling was a lay preacher at two churches in the Bude area of Cornwall, Truro Crown Court was told.
Mr Dowling met the boy when he was 10 through church activities and "took him under his wing".
He has denied six counts of indecent assault on a child and two counts of gross indecency with a child.
The assaults happened in the 1970s before Mr Dowling became a press spokesman for the Diocese of Truro, the court heard.
Jo Martin, prosecuting, said some of the assaults took place at Mr Dowling's house after the boy had been invited for dinner and on one occasion he was taken to a church on the north coast.
She said Mr Dowling took him up a tower and showed him the view, then took him to a room and assaulted him.
The alleged victim did not tell anyone when he was a child but later, when he was married, told his wife about the assaults.
He said when his wife rang up Mr Dowling, accusing him of being a paedophile, Mr Dowling replied "that was a long time ago".
He said he eventually went to the police after reading in news reports that Mr Dowling had admitted abusing five boys when he was a teacher at a private school in the 1960s.
Mr Dowling is currently serving a jail term for those offences.
The trial continues.
A former preacher indecently assaulted a boy on a visit to a church, a court heard.