Breakfast cereal he launched the Cornflakes brand, which overnight captured a national market. Soon there were forty rival manufacturers in the Battle Creek area. His brother William K. Kellogg (1860–1951) worked for him for many years until, in 1906, he broke away, bought the rights to Cornflakes, and set up the Kellogg Toasted Corn Flake Company. William Kellogg discarded the health food concept, opting for heavy advertising and commercial taste appeal. Later, his signature on every package became the company trademark. The second major innovator in the cereal industry was Charles W. Post, a salesman who was admitted to Kellogg's sanitarium as
Joseph Kellogg first commercial flour mill in Oregon. He also built several of the first sawmills. Kellogg's land claim was next to that of Lot Whitcomb, at Milwaukie. Kellogg, Whitcomb and William Torrence laid out the town site of what they hoped would be the principal city in Oregon. In Milwaukie, Kellogg built a sawmill and a schooner. Kellogg, Whitcomb and Torrence loaded the schooner with provisions from the adjoining farms, took it to California, and there sold both vessel and cargo, and with the proceeds they bought the brig "Forest", which they used in the lumber trade between Oregon and California.