Experts at the time were sceptical about North Korean involvement in the leaks, but a Bloomberg report suggested a Sony internal report linked the attack to a group associated with Pyongyang known as DarkSeoul, which wiped out the computers of South Korean banks and broadcasters in March 2013.
Britain's National Cyber Crime Unit said it had obtained critical evidence which was able to link the NHS attack to others already being investigated in the US.
Park, who USA officials believe is now in North Korea, faces charges that include conspiracy to commit wire fraud.
"This was one of the most complex and longest cyberinvestigations the department has taken", said John Demers, assistant attorney general for national security.
The U.S. Justice and Treasury Departments said Park Jin Hyok was "part of the conspiracy" that masterminded those notorious hacks "on behalf of the Government of North Korea or the Workers' Party of Korea".
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The complaint also alleges that Park was in China in 2014, but returned to North Korea shortly before the Sony attack. "If they don't, this president will act on behalf of the United States".
U.S. authorities say Park Jin Hyok was part of the state-sponsored "Lazarus Group".
In one attack, an email sent to a victim from Facebook alerting them to the fact that their account had been accessed from a different IP address was grabbed by the hackers and then resent with the hyperlink within the email changed from Facebook's website to a domain that they controlled.
No North Korean government officials were referenced in the complaint by name, though it does allege the government sponsored the attacks.
The 34-year-old worked "on behalf of the government of North Korea or the Workers' Party of Korea", according to United States authorities.
"The criminal conduct outlined in this case is intolerable", said Tracy Wilkison, the first assistant USA attorney in Los Angeles. According to the DOJ's complaint, the North Korean agent worked through a front company called Chosun Expo Joint Venture and operated out of both North Korea and China. In recent years the department has charged hackers from China, Iran and Russian Federation in hopes of publicly shaming other countries for sponsoring cyberattacks on US corporations.
The charges were announced as President Trump and his administration negotiations with North Korea to end its nuclear program.