COLUMBUS, Ohio — When the Army discharged Pvt. Donald Hallman in 1955 for being what it called a “Class II homosexual,” the 21-year-old was so scared of being an outcast that he burned all his military records, save for a single dog tag he hid away.

Mr. Hallman, a coal miner’s son who sang in a church choir in rural Alabama, says he never mentioned his military service again. He married a woman he had met at work, had children and wore a suit and tie to work each day.

“I hid it because it would have ruined my life,” Mr. Hallman said in an interview at his home here.

But this summer, Mr. Hallman, now 82, retrieved the dog tag from a keepsake box and began working through an application to the Department of Defense, asking that his decades-old discharge be upgraded from “undesirable” to “honorable.”

“I’ve gotten to a point in my life where no one can hurt me now,” he said. “I don’t care who knows, and I want to show I was an honorable person.”