Hayden Panettiere Grew Up in Front of the Camera. It Took a Toll.

At 11 months old, Hayden Panettiere appeared in a Playskool toy train commercial. By age 4, she was a recurring character on the soap opera “One Life to Live.” In the decades that followed, she starred in movies and television shows. Rarely was she out of a job.

But like many wunderkinds, Panettiere, who died on Sunday at 36, frequently seemed burdened by her success. Her well-doblockented struggles — with alcohol, drugs, body image, her family, her significant others — seem inextricable from the public scrutiny that lit up so much of her life.

“In an era of relentless paparazzi with an appetite for celebrity breakdowns, naysayers were certain this young starlet would crash and burn,” reads one description of “This Is Me: A Reckoning,” the no-holds-barred memoir that Panettiere released this year. “Not one to disappoint, she did.”

Panettiere seemed to have recently made peace with her thorny story, telling The New York Times in May that she maintained a “laundry list of aspirations,” including directing and producing, perhaps a lifestyle brand.

But on Monday, emergency responders who arrived at an apartment in Greenville, S.C., found Panettiere in cardiac arrest. A person with knowledge of the situation told The Times that an apparent drug overdose was the cause.

Born in Palisades, N.Y., in 1989, Panettiere rose to prominence as a child actor before her starring role as the supernaturally gifted cheerleader Claire Bennet in the hit NBC sci-fi drama series “Heroes.” She was offered the job on the spot, she recalled in her memoir, writing, “I thought my heart was going to explode with gratitude.”

Her newfound stardom led the paparazzi to wait for her outside the Universal Studios lot and chase her down the freeways of Los Angeles. The tabloids were ceaseless in their body-shaming. After one magazine spread pointed out the “cellulite” on a then-teenage Panettiere, the actress fell into a yearslong battle with body dysmorphia.

When Panettiere was around 16, someone on her team slipped her a pill intended to keep her energy up for “Heroes” press appearances, she recounted in her memoir. Those “happy pills,” she said, were “the gateway drug that ushered me toward the good of pharmaceuticals and the downfall of addiction.”

Panettiere’s family life was tangled up with her work. Her mother, the former soap actress Lesley Vogel, was a true “momager,” and her father, Skip Panettiere, complied, Panettiere wrote in the memoir.

“I know Dad had arguments between his head and his heart, with his heart questioning whether it was right to have his baby girl so busy all the time, being shuttled around from one audition to another,” Panettiere wrote. But she said he appeared to justify the arrangement, citing, for example, all the children she could meet at auditions.

In a statement on Sunday confirming Panettiere’s death, her father called her “an incredible light and a force of nature who brought immeasurable love and joy to all who knew her.”

Panettiere’s relationship with her mother bore the hallmarks of a business transaction, she told Jay Shetty on his “On Purpose” podcast.

“She was my boss,” Panettiere said. “That’s how I saw her.” She added that she felt she had to succeed professionally to earn her mother’s love, calling it “a tough pill to swallow.”

When, at 19, Panettiere finally told her mother that she no longer wanted to work together, Vogel responded, “You owe me” and walked away, the actress said on the podcast.

As a young woman in Hollywood, Panettiere also endured her share of predatory behavior. In her “Heroes” era, she said in her memoir, an unnamed Oscar-winning actor-director exposed himself to her at a party. Not long after, she had an encounter with an unnamed British singer-songwriter that she later told the journalist Jane Mulkerrins was “as close to being human trafficked as I have ever experienced.”

When she met Wladimir Klitschko, a professional boxer who became her longtime partner, Panettiere gravitated to how “safe” he made her feel, she said on the “Tamron Hall” talk show in May.

“I think my being with him actually ended up protecting me,” she said.

But there, too, she could hardly catch a break. After Panettiere gave birth to their daughter in 2014, she began to suffer from postpartum depression. That led to substance abuse issues that eventually forced her to take a hiatus from “Nashville,” an ABC and CMT drama about country music singers in the Tennessee capital. She would split up with Klitschko and lose custody of her daughter.

All along, the filming of “Nashville” had become “traumatizing” for Panettiere, as the show’s writers used her real-life struggles to inform her character’s story.

But, as she told The Times this year, she did as she was told, just as she always had.

“That was ingrained in me from a very young age,” she said. “I was a soldier. Never for a second did I think to say, ‘Hey, I’m not comfortable with this.’”