Thomas Kwoyelo, a mid-level commander in the notorious Lord's Resistance Army rebel group, was sentenced to 40 years in prison in Uganda on Friday for war crimes including murder, rape, enslavement, torture and kidnap.
Kwoyelo was convicted of dozens of war crimes in August, the first time an officer of his seniority had been tried by Uganda's judiciary.
Founded in the late 1980s with the aim of overthrowing the government, the LRA brutalised Ugandans under the leadership of Joseph Kony for nearly 20 years as it battled the military from bases in northern Uganda.
The insurgents carried out horrific acts of cruelty, including rapes, abductions, hacking off victims' limbs and lips and using crude instruments to bludgeon people to death.
"The convict played a prominent role in the planning, strategy and actual execution of the offences of extreme gravity," Justice Duncan Gasagwa, one of the four judges, said.
"The victims have been left with lasting physical and mental pain and suffering."
Kwoyelo avoided the death sentence because he was recruited by the LRA at a young age, was not one of the top-ranking commanders, and has expressed remorse and a willingness to reconcile with the victims, Gasagwa said.
Kwoyelo had denied the charges during the trial. His lawyer, Caleb Alaka, told the court he would appeal against both the verdict and the sentence.
In around 2005, under military pressure, the LRA fled to the lawless jungles of South Sudan, Democratic Republic of Congo and Central African Republic, where it also unleashed waves of violence against civilians.
Splintered elements of the group, including Kony, are believed to still live in those areas, although attacks are now infrequent.
The Ugandan military captured Kwoyelo in 2009 in northeastern Congo and his case crept through the Ugandan court system until he was convicted in August.
He was found guilty on 44 charges, 31 were dismissed as duplications of others while he was acquitted on three.
An arrest warrant was issued by the International Criminal Court's (ICC) against Kony in 2005, making him the court's longest standing fugitive.