The launch comes as South Korea and the United States prepare to wrap up 11 days of combined military drills.
Pyongyang has said it needs a military reconnaissance satellite to boost monitoring of US military activities.
The hackers were believed to be linked to a North Korean group that researchers call Kimsuky, and they carried out their hack via emails to South Korean contractors.
North Korea has repeatedly rejected accusations of abuses and blames sanctions for a dire humanitarian situation.
The Pentagon said that they cannot verify alleged comments by US Private King.
North Korea has tested rocket launchers for larger caliber shells, advanced cruise missiles and last month its newest ballistic missiles, including a solid-fuel intercontinental ballistic missile.
The reports come amid heightened tensions on the Korean peninsula as South Korea and the United States take steps to boost military readiness against North Korea's weapons program.
The USS Annapolis entered a naval base in South Korea' southern island of Jeju, to load military supplies while on an unspecified operational mission, the South Korean navy said.
“US SSBNs anywhere from the US West coast westward can strike targets in North Korea,” Van Diepen said. “Therefore, some US SSBNs are within range of North Korea at all times.”
Flight records show Flight 280 departed nearly an hour late that day, but it is unclear if that delay was due to King skipping the flight.