Byun Hui-su, 23, who was a staff sergeant before being discharged after she had the operation in Thailand while on leave, was found by emergency officials at her home in the city of Cheongju, south of Seoul.
There was no immediate word on the cause of her death.
A local counseling center, at which Byun was registered, reported to emergency officials that she could not be contacted since February 28, the local fire department said.
Cheongju police confirmed the dead body they found in Byun’s home Wednesday was the former soldier. Authorities said it appeared she had been dead for a few days.
Byun, who had expressed hope of continuing to serve in the military’s female corps, had been pursuing a lawsuit contesting her dismissal, with a hearing expected in April, according to a spokeswoman for military advocacy group Center for Military Human Rights Korea that had worked with her.
South Korea’s first transgender soldier, who was discharged from the military last year for having gender reassignment surgery, was found dead in her home on Wednesday, authorities said.