Teacher Kendall McKibben, 24, was arrested in Arsenal Street where a large crowd had gathered to witness the spectacle on June 30.
Magistrate Bina Chainrai told him: "Your behaviour has been disgraceful. If you are not able to control yourself when you have consumed alcohol, you should not drink."
"As a visitor in Hong Kong, to behave in this way has brought shame upon you."
When the prosecution allegations were read to him at San Po Kong Court, McKibben said he could not remember what had happened.
But he admitted indecent exposure and behaving in a disorderly manner while drunk. He was fined $2,000.
Albert Luk, defending, said McGibben came to Hong Kong for the handover intending to "have fun".
The sudden strip was due to the drink he had consumed. "He could not properly control himself. He is sorry about that and asked me to tender his apologies to the court," Mr Luk said.