The victim was found with wounds on his hands, waist and legs, and was weak as he hadn't eaten in days
Yohanes Syahputra was found late Thursday by villagers on Borneo island in an exhausted state, army spokesman Sabrar Fadhilah told AFP.
"Thanks be to God almighty, we have found one of the passengers of the downed helicopter," Fadhilah said in a text message.
"The victim was found with wounds on his hands, waist and legs, and was weak as he hadn't eaten in days."
Syahputra was aboard a Bell 412 helicopter with four other military personnel when it lost contact on November 24 over a remote stretch of Bornean jungle, the army said.
The wrecked chopper was found three days later, having crashed during a delivery run to a remote army post near the Malaysian border.
Three crew had died but one was found alive. The location was so difficult to reach the airman had to be winched by rope, the military said.
Syahputra however was not found and was feared dead, with the terrain deemed too inhospitable.
The chopper went down deep in the forested, mountainous interior of Borneo, miles from any major city.
A farmer discovered the soldier resting at a hut on the outskirts of a plantation, where he had been eating sugar for sustenance, local media reported.
He was taken to a villager's home in Long Sulit and offered food and water, the reports said.
Fadhilah said Syahputra would be evacuated for medical check ups at a hospital in Tarakan, one of the main cities on the north-eastern coast of Borneo.
The military has closely guarded the details surrounding the accident and discovery of Syahputra.
It's just the latest fatal crash for Indonesia's accident-prone military.
Twelve people were killed in March when a military helicopter went down in bad weather on Sulawesi in central Indonesia.
Three died when a separate military chopper crashed into a home in Central Java in July.
It's also not the first time a passenger has made a miraculous escape in an Indonesian air disaster.
Last year a man was found alive, naked and floating in a huge volcanic lake on Sumatra island, two days after the helicopter in which he was travelling crashed.
He was rushed to hospital after being found conscious but very weak, wearing only a black watch, in Lake Toba.