HONG KONG — A former Hong Kong hairstylist whose rapid rise to wealth culminated in the takeover of the British soccer team Birmingham City was convicted on Monday of five counts in the laundering of a total of nearly $100 million from entities including casinos and people the authorities have described as gang members.

A district court judge in Hong Kong ruled that Carson Yeung, 54, had given testimony “bordering on the nonsensical” as the defendant sought to explain the millions of dollars that had flowed into his bank accounts from sources including a Macau casino operator and a man identified by the Hong Kong police as a senior triad leader.

“He did not care where the money came from, and he did not bother to ask,” Judge Douglas Yau said Monday, adding that Mr. Yeung had lied throughout his testimony. “He was just making it up as he went along.”

Mr. Yeung, in a dark suit and tie, sat expressionless as the verdict was read in English and translated for him into Cantonese. Mr. Yeung had been free on bail throughout the trial but was taken into custody after the hearing Monday. He is scheduled to be sentenced Friday and faces a maximum prison term of seven years.