Royal Marine Alexander Blackman, also known as Marine A, was released from prison in the early hours of Friday.
The former Marine, who has served more than three years in prison for shooting dead an injured Taliban fighter in Afghanistan in 2011, was driven away from HMP Erlestoke, Wiltshire, at around 12.20am.
Blackman hid in the back of a black Audi estate vehicle as he was taken away.
The commando was jailed for life after he was convicted of murder in 2013. The conviction was quashed by the Court Martial Appeal Court and replaced with diminished responsibility manslaughter last month, following a high-profile campaign to free him.
Five judges ruled that Blackman was suffering from an “abnormality of mental functioning” at the time of the incident, when he was serving with Plymouth-based 42 Commando.
Speaking to the Daily Mail while awaiting her husband’s release, his wife Claire Blackman said: “‘I haven’t slept all week. I feel like a child waiting for Christmas.
“We have had so many setbacks over the years that I almost cannot believe it is really going to happen this time. I can’t wait to see him and spend some quality time together.”