The defendant was also ordered to pay €8,000 in costs and damages after a criminal court in Lecce, Puglia, ruled that writing fake reviews under a false identity constituted criminal conduct under Italian law.
TripAdvisor, which was a civil claimant in the case, hailed the decision as "a landmark ruling for the internet".
"Writing fake reviews has always been fraud, but this is the first time we've seen someone sent to jail as a result," said the website's vice-president and associate general counsel, Brad Young.
Its fraud investigators began probing the case in 2015, TripAdvisor said, when multiple hospitality businesses in Italy began alerting it to emails they had received offering to write favourable reviews on command.
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Despite the fraudster's attempt avoid detection by using a string of different usernames and email addresses, investigators were able to link him to thousands of attempted reviews of hundreds of businesses.
The site then notified the businesses concerned and bumped down their position in the site's popularity ranking, flagging listings with a warning to users if the suspicious reviews continued.
Meanwhile Italian police began preparing a criminal prosecution after they were tipped off by a restaurant owner in Trieste.
Italy has slammed TripAdvisor in the past for failing to crack down on fake reviews. In 2014 the Italian competition watchdog fined the site €500,000 – a penalty later overturned – for encouraging readers to believe that reviews were genuine, despite evidence that some most definitely were not.
Despite the sanctions, a year later an Italian food magazine was able to send a non-existent restaurant to the top of the TripAdvisor ranking in one small northern town, in a bid to demonstrate the ease with which reviews could be manipulated.
Since then, the site says, it has stepped measures to detect and punish review fraud. Business owners who have been approached by reviewers for hire are encouraged not to reply but report them directly to TripAdvisor's investigators.
"Online reviews play a major role in tourism and consumer purchasing decisions, but it's important everyone plays by the rules," said Pascal Lamy, chairman of the World Committee on Tourism Ethics (UNWTO).