In 1897, a farmer in Orrville, Ohio, named Jerome Monroe Smucker began selling stoneware crocks of apple butter from the back of a horse-drawn wagon. He signed the lid of each one, to vouch for its quality.

The J.M. Smucker Co. still sells apple butter with the family name on the label. It also sells Smucker jams and jellies, Jif peanut butter, Folger's coffee, Crisco shortening, Pillsbury cake mixes, Eagle condensed milk, Hungry Jack pancakes and R.W. Knudsen juices -- 2,100 products in all, which brought in $4.6 billion last year.

This is noteworthy but hardly unprecedented. Some of America's biggest companies took root in the 19^th century as family businesses selling a single product -- DuPont with gunpowder in 1802, Procter & Gamble with candles in 1837, General Electric with the electric lamp in 1892.

What makes Smucker unique is that, more than a century later, it remains a family-run business. Still headquartered in rural Orrville (population: 8367), the company has had five chief executives, all named Smucker -- J.M. (1897-1947), his son Willard (1948-1960), his son Paul (1961-1987) and, since then, Paul's sons Timothy and Richard Smucker, who currently share the job of CEO.

Fifth-generation cousins Mark Smucker and Paul Smucker Wagstaff are being groomed to succeed them. "We would like that, but it's not a fait accompli," Richard Smucker, the boys' uncle and their boss, told me when I visited the Smucker Co. last month.

I've got a story about J.M. Smucker in the current (Aug. 16) issue of FORTUNE; it's one of a series of profiles of FORTUNE 500 companies that I'm writing for the magazine. While working on the story, it struck me that the Smucker offers a interesting and little-known case study in sustainability: Why has this company, which for most of its life has focused on the prosaic business of making jellies and jams, lasted for 113 years?

And not just lasted, but thrived. As I wrote in the magazine:

Smucker's sales have exploded from $632 million in fiscal year 2000 to $4.6 billion in 2010, during which time the company acquired such well-known brands as Jif, Crisco, and Folger's. Profits, meanwhile, have grown more than 10-fold, from $36 million to $494 million. Shareholders have also fared well. Over the past 10 years the company has delivered a total return of 309%, compared with -15% for the S&P 500, notes Farha Aslam, an analyst with Stephens.

That is truly impressive. Farha Aslam, who follows the company closely, told me: "Tim and Richard are clearly focused on delivering shareholder value. They take pride in that." The soft-spoken brothers, who are both Wharton grads, led a strategic makeover of the company in the 1990s and engineered a series of shrewd acquisitions in the last 10 years.

But I believe that the Smucker's corporate culture, which has been shaped over the years by the family's religious values, has been the key to its staying power. Tim and Richard see themselves as stewards of a family business whose reputation for integrity and decency is one of its most valuable assets. They want to give their employees opportunities to grow along with the business. They still work in the small town where they grew up. And their unusual partnership, as co-CEOS, sets an example for everyone in the company; people are urged to collaborate, and the leadership style is more about "we" than "me."