Yeung, who had denied the charges of laundering $93 million (£55m) between January 2001 and December 2007, will be sentenced on Friday. He faces up to seven years in jail.
A former hair stylist to Hong Kong's rich and famous, Yeung had told the court he amassed his wealth through hairdressing, share trading, property purchases, gambling in the world's casino hub of Macau and other investments.
Prosecutors had pointed to what they said were suspicious cheque payments made to Yeung by employees of Macau companies, including a junket operator, which earns commissions from casinos to attract cash-rich gamblers.
Delivering his verdict to a packed courtroom after a trial that lasted more than 50 days, District Court Judge Douglas Yau said Yeung had lied about how he made his money and exaggerated the amount of cash generated by his hair salon business and through gambling.
"I find the defendant not a witness of truth. I find that he is someone who is prepared to, and did try to, lie whenever he saw the need to do so," the judge said.
Dressed in a dark suit and tie, Yeung appeared calm but looked tired during the court proceedings and did not react when the verdict was read out.
Yeung left the courtroom without commenting on the conviction. His lawyer, Graham Harris, declined to comment.
The trial has revealed the flamboyant businessman's close ties to Macau's casino world, both as an investor and gambler, and how that facilitated business investments that helped him amass his wealth.
The judge said he found it "extremely strange" that some of Yeung's business dealings were conducted without a written agreement, even when the amount of money involved was huge.
"Unless, of course, those engaged in such a transaction would rather there not be records," Judge Yau said.
Yeung initially bought 29.91 percent of the shares in Birmingham City Football Club in 2007 and then acquired the rest of the shares for approximately £81.5 million in 2009, through his company, Birmingham International Holdings Ltd.
He stepped down as chairman and executive director of the listed company last month while he awaited a verdict. A week later, the indebted parent said it was selling a 12 percent share in its UK subsidiary for HK$45 million (£3.5m) to a little-known Chinese advertising firm.
Officials at Birmingham International declined to comment on the verdict when contacted by Reuters on Monday. Officials at the football club were not available outside normal business hours in the UK.
Yeung was arrested in June 2011, when trading in shares of the football club's parent was suspended. They resumed trading on Feb. 7 and have risen 39 percent since then.
As a free financial centre, Hong Kong has become a popular place for Chinese to set up companies and conduct business, in some cases to obscure their assets through money-laundering.
A new anti-money laundering (AML) ordinance came into effect in April 2012, bringing stricter requirements for bank monitoring of customers and the reporting of suspicious transactions to authorities.
Last April the city's banking regulator doubled the size of its anti-money laundering team to strengthen supervision amid intensifying scrutiny of monitoring and compliance systems at global financial institutions.
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