A Taiwanese court found 13 officers guilty of involuntary manslaughter in the death of army corporal Hung Chung-chiu, but only one of the defendants is likely to serve time in jail.
The ruling angered the victim's family and the island's rights groups.
Eighteen officers were charged over Hung's death, but the Taoyuan District Court found only 13 were guilty.
It sentenced army company leader Hsu Hsin-cheng to eight months in jail; the others received terms of six months or less, but those could be converted to fines, court officials said.
Hung died of multiple organ failure on July 4 after being forced by his superiors to undergo solitary confinement and consecutive days of drill exercises at a military detention centre. They claimed he had violated military rules by bringing in a camera-equipped mobile phone.
He was three days away from completing his year-long compulsory military service.
The death sparked a protest by more than 200,000 people on August 3 and forced President Ma Ying-jeou's government to demand the defence ministry improve human rights and review disciplinary punishment in military compounds. It prompted the replacement of the military trial system with civilian trials in times of peace, and forced defence minister Kao Hua-chu to resign.
The court found there was no direct evidence showing that when Hung was ordered to perform the exercises, he was already on the brink of exhaustion from heatstroke.
Hung's family and Taiwanese rights groups called the sentences unacceptable. Hung's mother, Hu Su-chen, broke down in tears when the sentences were read out.
"Just one was given eight months while the rest can walk free!" she said. "How cheap can a life be and who is responsible for the death of my son?" Family members said they would appeal against the verdict.
Activist group Citizen 1985, which staged several protests including a mass rally outside Ma's office in Taipei in August, also described the verdict as unacceptable.