Before she became known as “America’s Mom” on “The Brady Bunch,” Florence Henderson was an established Broadway star and a frequent presence on television, including the first female guest host of NBC’s “Tonight Show.”

But it was for her role as Carol Brady, the calm, problem-solving mother of “The Brady Bunch,” a sitcom about a blended suburban family, that Henderson became nothing less than a television superstar.

She died Thursday at a Los Angeles hospital, one day after being admitted. She was 82. Her unexpected death was described as “heart failure” in a statement from her manager, Kayla Pressman.

“The Brady Bunch,” which also starred Robert Reed as a widowed father of three boys, ran on ABC-TV from 1969 to 1974 but seemed to grow in popularity through syndicated reruns that have kept it airing for decades. The entire “Brady Bunch” cast, including Henderson, reprised their roles for several TV specials over the years, as the show became an unexpected cultural touchstone.

Henderson’s character was memorably introduced at the beginning of the show’s jaunty theme song: “Here’s the story of a lovely lady who was bringing up three very lovely girls / All of them had hair of gold, like their mother, / the youngest one in curls.”

It was never revealed whether Henderson’s character was divorced or widowed, but she navigated the trials of parenthood with aplomb as the children of “The Brady Bunch” struggled to adapt to their new step-siblings.

During the show’s first season, Henderson captured the inclusive sense of family that the show embodied, by consoling Bobby, the youngest son of the newly united family, not to think of himself as a stepchild.

“Listen, the only steps in this house are those,” she said, pointing to the staircase, “the ones that lead up to your bedroom.”