Two of the men entered guilty pleas in the case, which centers on the"cyber theft" of at least $100 million worth of software and data, according to the Justice Department.
The hackers are accused of breaking into programs used for the Army's Apache helicopter pilot training, Microsoft's Xbox One consoles, and yet-to-be released video games "Gears of War 3" and "Call of Duty: Modern Warfare 3."
Those charged in the case teamed with others in the US and abroad to hack into networks of Microsoft, Epic Games, Valve Corporation, and the US Army, according to the indictment.
"Members of this international hacking ring stole trade secret data used in high-tech American products, ranging from software that trains US soldiers to fly Apache helicopters to Xbox games that entertain millions around the world," assistant attorney general Leslie Caldwell said.
An indictment returned in April and unsealed Tuesday charged the four with conspiracy to commit computer fraud, theft of trade secrets and other offenses.
Those named in the indictment were Nathan Leroux, 20, of Bowie, Maryland; Sanadodeh Nesheiwat, 28, of Washington, New Jersey; David Pokora, 22, of Mississauga, Canada; and Austin Alcala, 18, of McCordsville, Indiana.
Additionally, an Australian citizen has been charged under Australian law for his alleged role in the conspiracy, officials said, without identifying the suspect.
Officials said Pokora and Nesheiwat pleaded guilty in a Delaware federal court to some of the charges and are scheduled for sentencing on January 13.
Pokora was arrested on March 28, at the US-Canada border in Lewiston, New York. Officials said Pokora is believed to be the first person based outside the United States convicted of hacking into US businesses to steal trade secret information
According to the indictment, the group hacked into networks to steal the source code, technical specifications and related information for Microsoft's then-unreleased Xbox One gaming console, and other proprietary data related to the online gaming platform Xbox Live.
Other trade secrets stolen were from the Apache helicopter simulator software developed by Zombie Studios for the US Army and a pre-release version of Epic's video game "Gears of War 3."
The value of the stolen intellectual property and other losses was estimated between $100 million and $200 million.
Officials said they had seized over $620,000 in cash and other proceeds from the suspects.
This case is being investigated by the FBI, with assistance from the Department of Homeland Security, the US Postal Inspection Service and in coordination with the Western Australia Police and the Peel Regional Police of Ontario, Canada.