He was fined £19,000, and will be deported from the country after serving his sentence. His US-citizen wife - who worked alongside him - was sentenced to two years and must pay a fine of £14,500.
Mr Humphrey did not dispute breaching China's privacy laws at his trial at Shanghai Intermediate People's Court, where he was handed 30 months out of a possible 36-month maximum jail term.
He told the court he had always supported anti-corruption in China.
The couple were arrested last July, having completed an internal investigation for GSK, which is currently facing a separate corruption probe. No link between GSK and the case against ChinaWhys was made in the proceedings.
Humphrey and his wife, Yu, were detained soon after they completed their report for the pharmaceutical giant.
Mr Humphrey is a former Reuters foreign correspondent, and his wife an accomplished accountant. They commenced their Shanghai-based firm in 2003, helping firms screen potential business partners and employees at around £10,000 a report.
Their other clients are domestic and international large or medium-sized companies operating in manufacturing and finance, as well as law firms. Their company website says they provide 'discreet risk mitigation solutions' and corporate investigations.
Mr Humphrey explained to the court that his company would sometimes ask Chinese sources to provide private information, but added that these types of records were only a small part of his business, adding most of their research was undertaken using public information derived from internet searches, interviews, and site inspections.
Mr Humphrey said where he paid companies to undertake the service of business background checks in China for him, he did not pay them for the information they produced.
While he accepted this information could be private to the individuals concerned, he admitted he didn't understand Chinese laws related to information sourcing and privacy well.
His wife had advised companies in the US, Hong Kong and China in medical products and technology industries for over 25-years.
During the trial, she appealed to the court saying: "In other countries, we were able to conduct similar checks, including personal information and private transactions legally through the courts."
China's foreign business community has been watching the pair's year-long trial with interest and concern, especially since Beijing dramatically tightened controls over the gathering of corporate and personal information.
At the time of the couple's arrest last year, Shanghai police said 126 people were under investigation for illegally obtaining information, and 35 people had been arrested.
China has been cracking down on the exchange of corporate information since 2012, when a number of disclosures about possible financial misconduct by Chinese businesses were made.
Soon afterwards, new regulations appeared that prohibited government agencies disclosing company financial or commercial information without the company's consent.
Since then, it has become far harder for cross-border businesses in China to conduct due diligence on potential partners and suppliers or acquisition targets.