The idea of “who invented cereal” actually has two main answers, depending on what you mean by cereal.

Short answer

  • The first commercially successful cold breakfast cereal was Granula , invented in 1863 by James Caleb Jackson , a health spa owner in New York.
  • The most famous modern-style dry, flaked cereal (like what we think of today) was developed later by John Harvey Kellogg and his brother Will Keith Kellogg , who created wheat flakes and then corn flakes in the late 1800s.

Quick Scoop: Who invented cereal?

1. Before “cereal”: porridge and oats

Long before cereal boxes, people mainly ate:

  • Hot porridges from oats, wheat, or other grains.
  • Heavier breakfasts with meat, bread, and potatoes, especially in the 18th–19th centuries.

These weren’t “boxed cereals” yet, just cooked grains.

2. James Caleb Jackson – the first cold cereal

Most historians credit James Caleb Jackson as the inventor of the first cold breakfast cereal.

  • In 1863 , Jackson, a religious, health-focused doctor who ran a sanitarium in New York, created a cereal he called Granula.
  • It was made from baked graham flour crumbled into nuggets, so hard it had to be soaked overnight before you could eat it.
  • This is widely considered the first cold breakfast cereal sold commercially in the United States.

So if your question is “who invented the first cold breakfast cereal?” → James Caleb Jackson.

3. John Harvey Kellogg – health cereal to corn flakes

A few decades later, another health-obsessed doctor picked up the idea: John Harvey Kellogg.

  • Kellogg was a Seventh-day Adventist doctor who ran the Battle Creek Sanitarium in Michigan, promoting a very strict health regime and vegetarian diet.
  • Inspired by Jackson, he invented his own version of a grain-based health cereal around the 1870s–1880s , also initially calling it Granula.
  • Because Jackson already had a cereal by that name, Kellogg was threatened with a lawsuit and changed the name to “Granola.”

Kellogg’s big leap came when he and his team experimented with cooked grains that were then rolled out and baked:

  • In 1894 , John Harvey Kellogg developed a process to make flaked cereal and later received a patent titled “Flaked Cereals and Process of Preparing Same” in 1896.
  • His brother Will Keith Kellogg refined the recipe and later used corn instead of wheat to make what we know as corn flakes.
  • John H. Kellogg is officially credited with inventing Corn Flakes®, the first dry, flaked breakfast cereal , which transformed the typical American breakfast.

So if your question is “who invented modern flake cereal like cornflakes?” → John Harvey Kellogg , with crucial help and commercialization by Will Keith Kellogg.

4. So who “really” invented cereal?

Different answers make sense depending on how you define “cereal”:

  • First cold cereal ever sold:
    • James Caleb Jackson – invented Granula in 1863.
  • First dry, flaked cereal (corn flakes–style):
    • John Harvey Kellogg , patented flaked cereals in the 1890s and invented Corn Flakes®.
  • Person who turned it into a giant business and brand:
    • Will Keith Kellogg , who founded the Kellogg Company in 1906 and marketed cornflakes on a huge scale.

You can think of it like this:

  • Jackson lit the spark ,
  • John Harvey Kellogg turned it into a new kind of food ,
  • Will Kellogg built the global cereal industry on top of it.

5. Mini FAQ

Was cereal invented to be healthy?
Yes. Early cereals were marketed as health foods meant to replace heavy, greasy breakfasts and support digestion at health spas and sanitariums.

Is there a single “inventor of cereal”?
Not really. Cereal evolved in steps: porridge → hard health cereal (Jackson) → flaked cereal (Kellogg) → sugary branded cereals.

TL;DR:

  • James Caleb Jackson invented the first cold breakfast cereal (Granula) in 1863.
  • John Harvey Kellogg (with his brother Will) later invented flaked cereals and Corn Flakes® , which basically created the modern cereal aisle.

Information gathered from public forums or data available on the internet and portrayed here.