Lance Corporal Joseph Scott Pemberton said he was “extremely grateful” to president Rodrigo Duterte for pardoning him.
He also expressed his “most sincere sympathy” to the family of Jennifer Laude, who he was convicted of killing in 2014 after finding out that she was transgender in a motel northwest of Manila.
During his five-year confinement, Pemberton said he spent “much time contemplating the many errors” he committed the night Ms Laude died.
“He wishes he had the words to express the depth of his sorrow and regret,” Pemberton’s said in a message ahead of his departure, which was issued by his lawyer Rowena Garcia-Flores.
Philippine immigration officers and American personnel escorted the 25-year-old Marine, who was in handcuffs and wearing a face mask, from his cell in the main military camp in metropolitan Manila to the airport, where he boarded a military aircraft.
The US Embassy said “all legal proceedings in the case took place under Philippine jurisdiction and law” and that “Pemberton fulfilled his sentence as ordered by Philippine courts”.
On Monday, Mr Duterte granted an “absolute and unconditional pardon” to Pemberton in a move that caught many by surprise and was condemned by left-wing and LGBTQ groups.
Debate has brewed whether the Marine, whose detention was arranged under the treaty allies’ Visiting Forces Agreement, can be covered by a Philippine law that grants shorter jail terms to ordinary prisoners for good conduct.
The Regional Trial Court in Olongapo city, which handled Pemberton’s case, ordered authorities to release him early from detention for good conduct, but Ms Laude’s family appealed against the order, blocking the marine’s early release.
The court order rekindled perceptions that American military personnel who run afoul of Philippine laws can get special treatment under the allies’ agreement, which provides the legal framework for temporary visits by US forces to the country for large-scale combat exercises.
Pemberton, an anti-tank missile operator from New Bedford, Massachusetts, was one of thousands of American and Philippine military personnel who participated in joint exercises in the country in 2014.
He and a group of other marines were on leave after the exercises and met Ms Laude and her friends at a bar in Olongapo, a city known for its nightlife outside Subic Bay, a former US navy base.
Ms Laude was later found dead, her head slumped in a toilet bowl in a motel room, where witnesses said she and Pemberton had checked in.
A witness told investigators that Pemberton said he choked Ms Laude after discovering she was transgender.
In December 2015, a judge convicted Pemberton of homicide, not the more serious charge of murder that prosecutors sought.
The Olongapo court judge said at the time that she downgraded the charge because factors such as cruelty and treachery had not been proven.
