Who were your parents before they were your parents?

Much of what we know comes from hearing Mom and Dad talk about their childhoods and youthful foibles, their early setbacks and notable milestones. Nevermind the scant details and gaps in the timeline.

For some people, a fuller picture emerges only after Mom and Dad die, leaving behind a trove of old letters and keepsakes. In cleaning out attics, emptying filing cabinets and opening trunks, families unearth letters that cast their parents—and their grandparents—in a whole new light.

We asked readers to share how old letters gave them a new perspective of their parents as “people.” Below are their stories of heroic acts and unflagging devotion, as well as shameful secrets and unspoken pain.

A terrifying margin call

When sorting through his father’s papers, Michael Garrett came across a Western Union telegram dated Nov. 5, 1929, one week after the Black Tuesday stock-market crash.

At the present market your account requires $2,000 additional margin. Please deposit this sum at our main office before ten o’clock tomorrow November sixth without fail.

The recipient was Louis Goldfarb, Garrett’s paternal grandfather, who had just one day to come up with $2,000 (roughly $35,000 in today’s dollars) to send to his brokerage firm.

As a teenager, Garrett had read about the stock-market crash and Great Depression in history classes. But that yellowed, crinkled telegram made it real for him, especially since it likely arrived when Goldfarb’s wife was pregnant. “If you’re a student in high school, you can’t imagine what the terror must have been like for my grandfather,” Garrett says. “It’s different than reading about it in a textbook on page 343.”

Garrett, who is 58 and lives in Montclair, N.J., found the telegram in 2007, by which time he had two children of his own. “Having started a family myself made it possible to contemplate the dread and fear my grandfather must have felt,” he says.

Did his grandfather’s financial losses affect how Garrett’s father raised him? He can only speculate. “Dad always talked about not taking on debt, living at your means, not buying things you can’t afford,” Garrett says. “One morning, as Dad was getting dressed for work, an ad for home-equity loans came on the radio. The dialogue was of a couple that could get a pool just like the Johnsons down the street. My dad said, ‘There’s an ad telling you to take on more debt so people will think differently of you, that you have more money than you really do.’ ”

A wartime love?

When cleaning out his widowed father’s house, David Flack discovered a mystery at the bottom of a trunk. Along with his paternal grandfather’s dog tag from World War I was a letter from a woman in France, dated Oct. 15, 1921. In reading between the lines, Flack thinks his grandfather had given a widowed Frenchwoman money to come to America. But in her letter, the woman said she had decided to remarry and remain in France. The nature of his grandfather’s relationship with the woman remains a mystery, Flack says. Were they just friends or was there something more?

“As I reflect back, I was 12 years old when [my grandfather] died,” says Flack, a 65-year-old pathologist in Wichita Falls, Texas. “Gosh, I wish I had been wiser and smarter to ask more questions.”

After a few personal comments, the letter ends with:

“I will not close my letter without telling you the thankful remembrance and affection we keep in all of France for the valorous soldiers and friends who came to help us during the terrible days of the war. Believe, monsieur, in my best feelings.”

The letter, along with other artifacts from WWI, gave Flack a new perspective on what doughboys like his grandfather lived through. “They get on a troop ship, all crammed in, and spend two weeks in the ocean in dangerous circumstances getting to France,” he says. After landing, they faced the prospect of trench warfare in appalling conditions. Compare that to today, “when we complain when the air conditioning goes out,” Flack says. “It just reinforced how silly it is for me to get upset over little things.”

Dust Bowl

Lee Mequet’s discovery conjures up images of Dust Bowl-era hardships. Mequet, who lived in Dana Point, Calif., shared this account with The Wall Street Journal in November. Regrettably, she died at age 82 the following month. With permission from her family, here is a summary of her story.

When Mequet’s mother died, the family found a box filled with letters from her father written in the 1930s. Mequet’s parents were married on New Year’s Eve in 1929—she was 17 and he was 27—but the letters revealed that the couple spent the next eight years apart.

While Mequet’s mother lived with her sisters in Chicago, her father tramped the country taking on various jobs. He ended up in Los Angeles in 1933 amid the Great Depression. His letters told of out-of-work men sharing a room with others and, when they got lucky, splitting up leftover food if one of them got a job at a restaurant. He would sit for hours in a “chilled” movie theater to escape the heat.

His letters teased her with the signoff, “Your constant husband. Are you still my constant wife?” In January 1938, her mother apparently was fed up and asked for a divorce. In response, his next letter rages, “You had your divorce the second you asked for it!” But obviously they made up, Mequet said, because a following letter detailed plans to pick her up at Los Angeles’s Union Station.

The couple’s first child was born in November 1938, and perhaps inspired by the signoff in the letters, they named her Constance. The couple was married for 50-plus years.

Secret shame

Shortly after her father died in October 2017, Janice Kearney and her brother discovered a small box in his dresser that they hadn’t seen before. Inside was a one-page letter dated March 1955. In it, Kearney’s grandfather, Robert Weaver Jr., asked his son, Robert Weaver III, to pick up some groceries and bring them to his third-floor apartment, saying he was too sick to get out and couldn’t even get his shoes on. He also asked his son to take his rent to his landlord. The note closed with: undefined undefined “Hoping this doesn’t inconvenience you too much and trusting to your generous nature I await your arrival.”

Kearney’s grandfather died three weeks later.

There had always been some mystery around her father’s family. “His father didn’t seem to be in the picture beyond a certain point, and my dad wouldn’t talk about it,” says Kearney, who is 60 years old and lives in Deatsville, Ala.

“I’m a paralegal by trade, and in 2007 I started doing genealogical research on both sides of my family. In 2012, I noticed that the 1940 census listed my grandfather’s residence as Eastern State Penitentiary in Philadelphia. I asked [my dad] several times about it. But at that point, he was starting to show signs of dementia. All he would ever say is, ‘Well, he got into a bit of trouble.’ ”

Ultimately, Kearney discovered that her grandfather had been convicted as a sexual offender. “It was a big ‘Aha!’ moment. I knew why it had been such a secret,” she says. “I don’t even think my mother knew about any of this.”

It also made Kearney realize that she didn’t know her father as well as she thought, and wishes he had felt he could talk openly about his childhood. “We certainly wouldn’t have held his father’s transgressions against him,” she says. “Reading this letter made me realize this additional heavy burden he’d struggled with from age 14 to almost 91, and I just wanted to hug him and tell him I loved him. It made me see him as more human and more like a person than just ‘Dad.’ ”

Still, she believes her father was able to put the struggle behind him. “My father clearly got past things and moved on to a better life,” she says. “He was such a good dad.”

Homesick in America

In going through some old files, Sunder Joshi came across two letters that had been written by his parents around 1998. For some reason, they were never mailed. In reading his parents’ words, Joshi was so stunned that he had to sit down and collect his thoughts. In the letters, addressed to their former neighbors in India, Joshi’s parents, Devshankar and Sulochana Joshi, expressed the loneliness and sense of isolation they felt after moving to the U.S.

The couple had come to America when they were in their 70s to be closer to their three children, who had already immigrated to the U.S. for work. The parents rotated among their children’s homes for several months at a time and would spend several months in Mumbai when they were still able to travel.

In the letters, Joshi’s parents said that they enjoyed spending time with their children and grandchildren, but that the families had busy schedules. They also struggled to make new friends. Joshi’s father wrote about seeing Indian-looking men at the mall, but if anyone stopped to speak, their chats were brief. On walks around the neighborhood, the parents said they met nice people, but they didn’t feel a sense of community.

It was nothing like their old condo building in Mumbai, where residents spent long hours together in the building’s common spaces. Neighbors were like family and could generally come and go from apartments as they pleased. Ordinary people like street vendors and bus drivers knew them by name.

“Reading these letters, my immediate thought was, why did I not see this? Why did I not spend more time with them?” says Joshi, 74, a retired executive with the American Heart Association who lives in Orinda, Calif.

“On the weekends, we would go places. We would take family vacations, which they enjoyed. But they never shared with us that they were missing their home or that we weren’t spending enough time with them,” Joshi says.

His father died in 2005, and his mother died in 2014. Now that he has children and grandchildren with busy lives of their own, Joshi says he better understands what his parents were going through. “Just spending time with them would have made a difference,” he says.

Beth DeCarbo is a writer in South Carolina. She can be reached at reports@wsj.com .