His court hearing took place in the US territory of Saipan. He left the UK on Monday after being released on bail from the high-security Belmarsh prison , Julian Assange.
Assange told the court he had violated US law by facilitating the leaking of secrets, but that espionage was also an infringement of freedom of expression.
The US extradition request for the WikiLeaks founder on espionage charges has been withdrawn. He will soon fly to his native Australia to be reunited with his wife, Stella, and their two children, Gabriel and Max.
WikiLeaks said that if US District Judge Ramona Manglona grants the request, Assange will arrive in the Australian capital, Canberra, at 6:41 pm local time (9:41 am GMT).
The 52-year-old appeared in court wearing a dark suit but loosened his tie after flying in a chartered plane from London’s Stansted Airport and stopping in Bangkok for refuelling.
The flight cost $500,000 (£394,000) but Assange called for “urgent donations” to cover the “huge debts” he owed on the flight.
In court, Assange answered Judge Manglona’s basic questions and appeared to listen intently as the terms of the deal were discussed.
As a condition of his confession, he will be asked to destroy any information provided to WikiLeaks.
The hearing was held in the US territory of Saipan because Assange refuses to travel to any of the 50 US states and the court is closer to Australia.
US prosecutors had accused Assange of endangering life by helping former US Army intelligence analyst Chelsea Manning steal diplomatic cables and military files that WikiLeaks posted online in 2010.
He has been embroiled in a legal battle over extradition in the UK and has been in the country since May 2019, having been held in Belmarsh after entering the Ecuadorian embassy in London in 2012.