Benjamin Thomas's youngest victim was 11 and his oldest 34.
As well as the abuse, he made secret videos when they were showering or using the toilet.
Thomas's "dark secret" lasted for almost 30 years, beginning when he was 14 or 15, said the judge at Mold Crown Court in Flintshire.
He pleaded guilty to 40 offences including sexual activity with a child, sexual assaults, attempted sexual assaults, indecent assaults, voyeurism and making indecent videos of children.
Thomas, 44, worked on Wales Today and Welsh language children's programme Ffeil, and was pastor of Criccieth Family Church in Gwynedd until his arrest last year.
Judge Timothy Petts said the former presenter, who is married with children, had "struggled to reconcile his faith and sexuality", but that it was no excuse.
The court heard the vast majority of his victims were teenage boys and his preferred method was to wait until they were asleep to abuse them, often at Christian camps and conferences.
The judge said Thomas had a "facade of respectability" in his trusted position as church pastor.
His abuse was revealed when one victim had the "courage to come forward" and Thomas was reported to police, Judge Petts said.
When first interviewed, Thomas, from Flint, answered "no comment", but three weeks later he asked to be re-interviewed and confessed.
Many of his victims were unaware they had been abused until they were traced by detectives, and not all have been found.
The judge - who jailed Thomas for 10 years and four months - said he would remain on the Sex Offenders Register for life.
He told Thomas: "For nearly 30 years, until your arrest in September 2019, you hid a dark secret, namely that you were a prolific sex abuser.
"You know the harm you have caused to your victims and the wider impact your crimes have had upon your family and the church community."
Detective Chief Superintendent Gareth Evans, from North Wales Police, said Thomas should have "provided inspiration and guidance to young people, but instead caused real damage to young lives".
A spokesman for NSPCC Cymru said: "His offending will have had a profound effect on many of those he abused and it is vital they are able to get all the help they need to move forward with their lives.
"Thankfully, Thomas's campaign of abuse has now been brought to an end and he is rightfully facing time in jail."