Leonard Marsh, a former window washer who helped found Snapple, the beverage concern, and was its longtime president and chief executive, died on Tuesday at his home in Manhasset, on Long Island. He was 80.

His son-in-law, Jack Ross, confirmed the death.

With his brother-in-law, Hyman Golden, and a childhood friend, Arnold Greenberg, Mr. Marsh began what became the Snapple Beverage Corporation in New York City in 1972.

The company, known early on as Unadulterated Food Products, was created to sell fruit juices to health food stores. A part-time venture, it did modestly at first.

But the story of Snapple — based for many years in Valley Stream, N.Y., and among the first to make a wide line of juices and other drinks from natural ingredients — would become a latter-day Jewish Horatio Alger tale. By 1994, when it was bought by the Quaker Oats Company for $1.7 billion, Snapple was recording annual sales of about $700 million.