Army Master Sergeant Omar Velez-Pagan, 37, was given the punishment yesterday by the military court in Fort Bragg, North Carolina after being convicted Monday of the June 2014 murder of Vanessa Rodriguez, 25, Panama's foreign ministry said in a statement.
He was found guilty of killing her by crushing her head with his car, as well as adultery, steroid use and obstructing justice by trying to hide her body in rural land near a river in southern Panama.
Velez-Pagan last week admitted in court to all the crimes except murder. He was arrested in 2014 by Panamanian police and handed over to US officials, who sent him to the United States for detention and trial.
Rodriguez's parents previously said they feared Velez- Pagan would escape punishment, but reportedly expressed satisfaction with his conviction.
The US soldier was stationed in Panama on a one-year posting to help train a local police unit. While there he cheated on his American-based wife with Rodriguez, breaking military rules.