Ye Khaung Kyaw, also known as Danny Kyaw, was freed following a ruling by a court in Yangon, Myanmar's largest city, according to a legal official familiar with the case, who spoke on condition of anonymity because he was not authorised to release information.
Kyaw and the two other men charged in connection with the case have said the allegations against them are groundless.
Acting Police Brigadier General Soe Lin Aung, a spokesperson for Myanmar's Home Affairs Ministry, confirmed that the court concluded proceedings in Ye Khaung Kyaw's case on Tuesday but declined to provide further details.
It remains unclear whether he was convicted, had the charges dismissed or withdrawn, or was ordered to be deported.
Kyaw was detained in June around the same time as former chamber president Adam Castillo, a US businessman who was released last week and deported without explanation.
The chamber's current board accused Kyaw , Castillo and former board member Munimul Islam of breach of trust and misappropriation of association assets in connection with a $US300,000 ($A423,600) contract with the US-based lobbying firm Mercury Public Affairs.
Islam lives outside Myanmar and has not been detained.
The chamber is usually known as AmCham.
Myanmar's military-backed government released no official statement.
Officials at the court and the police station in Yangon's Pabedan township, where Kyaw faced trial, did not respond to requests for comment.
Authorities in Myanmar, which is currently in the midst of a civil war, rarely speak to the international media.
Supporters of the three men said the allegations were baseless and contradicted by documentary evidence.
The police complaint did not specify Kyaw's exact role in the alleged misconduct during his tenure as executive director.
AmCham's complaint centred on Castillo's creation of the US-Burma Economic Forum as a lobbying organisation during his presidency from 2023 to 2025 and a contract signed with Mercury in 2024.
DFAT confirmed that it had provided consular assistance to an Australian in Myanmar but declined to comment further, citing privacy obligations.
