Christopher Hodder set up a fake online profile and pretended to be a girl as he tricked his victims into providing intimate images of themselves.
Hodder, 31, from Kirkby Stephen in Cumbria, admitted 19 offences at Carlisle Crown Court.
The father of one of his victims said the family's lives had been ruined.
The man said: "This perverted monster should never be allowed to walk the streets again."
The court heard Hodder had been sentenced for a previous grooming crime in 2013. Part of his punishment was not to contact any children aged under 16 via the internet.
But last year police unearthed a catalogue of new offences after learning Hodder had communicated with a teenage boy using social media.
Officers found he had targeted 13 separate young victims including two brothers.
Hodder, of Union Square, admitted five counts of causing or inciting a child to engage in sexual activity, eight attempts to do the same, two breaches of a court order he was given in 2013 and several  charges relating to indecent images of children.
Judge Tony Lancaster said Hodder should be subject to an extended three-year licence period.
Judge Lancaster told him: "Your offending was mean, volatile and predatory."
A "perverted monster" who hunted out and sexually groomed 13 boys on Facebook has been jailed for four years.