A teenager "put lives at risk" when he posted thousands of US security agents' details online, a court has heard.
Kane Gamble, 18, targeted CIA, FBI and US Department of Justice databases from his bedroom in Leicestershire.
A sentencing hearing at the Old Bailey was told Gamble, who has admitted a number of charges, bragged of accessing the email and phones of senior figures.
His defence said he was on the autistic spectrum and was motivated by politics, not money.
Between June 2015 and February 2016, when aged 15 and 16, Gamble tricked call centre and helpline staff into revealing broadband and cable passwords from his bedroom on a housing estate in Coalville.
Using that information he targeted high-profile figures such as the then CIA Director John Brennan and Deputy Director of the FBI Mark Giuliano.
He then sent emails from agents' accounts and accessed sensitive military information.
Gamble even managed to use the TV in the house of then US Secretary of Homeland Security Jeh Johnson to post the message "I own you".
He took over the home phones of two senior security officials and diverted calls to the Free Palestine Movement.
While using an anonymous Twitter account he tried to justify his actions - in conversations with journalists - by saying he was angry about "corrupt and cold-blooded" US action in the Middle East.
Prosecutor John Lloyd-Jones QC said Gamble told others he knew he was "putting lives at risk" by releasing names of security staff but compared that to the US "killing innocent civilians".
His defence said Gamble was technically gifted but emotionally immature and on the autistic spectrum.
Also, they said, at no point did he attempt to profit from his actions.
Gamble pleaded guilty at Leicester Crown Court last October to eight charges of performing a function with intent to secure unauthorised access to computers and two charges of unauthorised modification of computer material.
He will be sentenced when the hearing resumes at a later date.