Colin Patterson, 51, from Newcastle, contacted a fake profile created by the Dark Justice group.
During conversations on the internet, he asked for sex, sent naked pictures and arranged a meeting.
The former shipyard worker had admitted attempting to meet a child following sexual grooming at a previous hearing.
At Newcastle Crown Court, prosecutor Tim Gittins said the vigilante group had set up the profile on the website Badoo as a girl named Tasha.
"They were careful that contact was initiated by the defendant and he contacted the profile in January," he said.
"It was made clear to him immediately that he was conversing with a 14-year-old and asked if that was acceptable to him.
"The defendant's conversations moved quickly towards sexual matters and asking to meet her."
Mr Gittins said Patterson sent two pictures of his genitalia, which was part of the 120 pages of conversation between them.
A rendezvous was arranged at the Centre for Life, in Newcastle city centre.
When Dark Justice arrived they stopped a passing policeman who arrested Patterson.
Jailing him, Judge Penny Moreland also placed him on the sex offenders' register for 10 years and made a sexual harm prevention order lasting for 10 years.
Shaun Routledge, defending, said: "He does not seek to blame anybody but himself and there are clear indications of remorse."
Dark Justice, who are a two-man team, welcomed the sentence and said their work had now resulted in 18 arrests.
A man who thought he was meeting a 14-year-old girl for sex but had been ensnared by internet paedophile hunters has been jailed for two years.