Last year, Byun won a court decision recognizing her as female, and the United Nations Human Rights Commission issued a statement to the South Korean government, that the discharge represented a violation of international human rights law.
Byun then initiated a lawsuit against the military for unlawful discharge, with the first hearing scheduled to take place in April of this year.
"It's hard to imagine what it must have been like for her to be abandoned, even betrayed," said Cho Kyu-suk, a member of the Center for Military Human Rights, which has been working with Byun.
Cho said that discrimination against LGBT+ people is prevalent in South Korean society, but that the discrimination is expressed differently in the military.
"Discrimination is more amplified in the military because we have a conscription system in which all young males [serve] about a year-and-a-half," Cho told DW.
The military's discrimination is not limited to transgender people.
In 2017, after a video surfaced online of two male soldiers having sex, the South Korean military conducted an investigation, seizing and forensically examining cell phones, interrogating troops, and charging more than a dozen with having homosexual intercourse, which is illegal in the military, even when off duty.
Military prosecutors won four convictions, with three soldiers serving months-long jail sentences.
The military's ban on gay sex is a remnant of South Korea's time under US protection and influence after the Korean War.
"The US criminalized same-sex relations in its military code of justice in the 1950s, and it was imported into South Korea," said Cho.
South Korean politicians have been generally slow to protect the LGBT+ community from discrimination, and have often expressed the opposite of such support.