An Australian diplomat fell to his death from the balcony of his Manhattan apartment on Wednesday morning after a night out celebrating Australia’s “yes” vote for gay marriage, the police said.

The diplomat, Julian Simpson, 30, had returned home with friends and headed to the seventh-floor balcony of his Clinton Street apartment on the Lower East Side to take in the Empire State Building. The spire was lit in rainbow colors that night to celebrate the Australian decision, in which more than 60 percent of the over 12 million voters who turned out on Wednesday approved legalizing gay marriage.

On the balcony, at about 1:30 a.m., Mr. Simpson, who served as second secretary to the Australian mission, began to twirl around a female colleague, distressing her, according to the police. A few moments later back inside, he was confronted by her husband, the police said. The two men stepped back out to the balcony. There, Mr. Simpson told his colleague’s husband that his intentions were never to scare his wife, according to a police official who declined to be named because the investigation is continuing.

By means of an apology, the police official said, Mr. Simpson suggested the two play a so-called trust game. “I will prove it that you can trust me,” Mr. Simpson told the colleague’s husband, the official said. “Let’s play the trust game.” In the course of the game, which was not described, Mr. Simpson fell off the balcony, landing five stories below.