William Post, a businessman who was credited with a significant role in inventing Pop-Tarts, a classic American snack and cultural touchstone with an enticing sweetness and simplicity, died on Feb. 10 in Grand Rapids, Mich. He was 96.

His death was confirmed by his son, Dan Post, who said his father had died of heart failure in a senior living community.

Mr. Post led the bakery plant that developed the first Pop-Tarts for Kellogg’s in 1964, his son said. The snack quickly became a popular treat for many people in the United States, including Mr. Post’s children, who were among the first taste testers.

Today, billions of Pop-Tarts are sold each year, according to Kellogg’s. They have also been depicted on murals, showcased in museums and parodied by “Saturday Night Live.” And later this year, they will star in “Unfrosted: The Pop-Tart Story,” a farcical chronicle of the 1960s race to win the breakfast-pastry wars, directed by the comedian (and Pop-Tarts enthusiast) Jerry Seinfeld.

Over the past 60 years, Pop-Tarts have expanded from four flavors to more than 30. But they’ve also maintained the classic form that has made them an American institution: two thin layers of dry, rectangular pastry with a sweet filling and frosting.

William Post was born on June 27, 1927, in Grand Rapids. He was one of seven children born to Henry Post and Johanna Jongsta, Dutch immigrants. His father, who was self-employed, drove a truck that he used to empty the ashes that people would take out of their coal furnaces.