The allegedly hacked information about members of the air force, army and navy included photos and ranks of personnel, SITE Intelligence said.
The hacking group said it took the information from government servers, databases and emails.
The self-proclaimed hackers said the 100 military staff had targeted the Islamic State group in Iraq, Syria and Yemen, and called on sympathisers to mount attacks.
Defence Department and FBI officials told The New York Times they were aware of the threats and were investigating the website.
The United States is leading an international coalition targeting the Islamic State group in Iraq and Syria, where the Islamist militants have taken over swaths of territory.
