John Stevenson Wright was sentenced at Manchester Crown Court to 18 months for sexually abusing Darren Kenny.
The court heard the offences took place when Wright worked at a pub run by Mr Kenny's parents in Rochdale.
Wright, 68, abused Mr Kenny as a teenager when he used to sleep over at the pub.
He was convicted of gross indecency, indecent assault and inciting a child under 16 to engage in a sexual act between 1978 and 1981.
Wright's sentence will be added to the 22 years he is already serving for sexually abusing boys.
Mr Kenny, 50, an officer with Greater Manchester Police in Tameside, was repeatedly abused as a teenager and thought Wright was dead until he typed his name into an internet search engine.
While looking for his abuser's obituary, he was "horrified" to learn Wright had been jailed for child sexual abuse in Rochdale.
He added: "We had been told he had died - I had my closure and then when we found out he wasn't dead I had no closure any more and I needed it back."
Mr Kenny, who has waived his right to anonymity, contacted the officer who had investigated Wright and said: "I've got another victim - me.
"Even if wasn't a policeman I would have come forward.
"The length of sentence isn't important... returning the guilty verdict is what is important."
Mr Kenny encouraged other abuse victims to speak out.
"Look at me - I'm here, I'm a 50-year-old cop, and if I can do it I'm sure they can."

Lisanne Beck, 47, allegedly performed a sex act on Simon Murphy, 48, during a Paloma Faith set in September.
The Old Bailey heard the couple were filmed conducting the alleged behaviour, but the jury failed to reach a verdict and were discharged.
The pair, from Swansea, denied outraging public decency.
Judge Peter Rook QC has given the prosecution until Thursday to decide whether to pursue a retrial.
He said: "Whatever the Crown says, it will have been a chastening experience over the last few days, I'm sure everyone will agree with that."
During the hearing prosecutor Tom Cleeve told jurors while "there are some amusing aspects to it... it was not funny at the time" and a 16-year-old girl had to be shielded from what was going on.
He said the two defendants were of "previously good character, but in that afternoon I'm afraid they blotted their copybook".
During the hearing Ms Beck said the film showed she was trying to wake her boyfriend up, while Mr Murphy's legal team said he was completely unaware of what his girlfriend was doing.
A police officer who thought his childhood abuser had died before he chanced across him online has said the man's conviction brought him "closure".
[NEXT_CONCEPT]
A couple accused of carrying out a sex act at a BBC Radio 2 concert in Hyde Park must wait to hear if they face a retrial after the jury was discharged.