Kelly Johnson formulated the KISS principle in the mid-1900s while working as an engineer for the Lockheed Skunk Works, Lockheed Martin's advanced aircraft development program.

Johnson coined the KISS principle during a long engineering career of designing systems with simple repair capabilities, using tools and skills used by average mechanics. Today, this term is frequently used in software design, where function creep and instruction creep can make programs unmanageable over time.

The KISS principle is similar to older concepts:

• Albert Einstein: "Everything should be made as simple as possible, but not simpler." This means that one should simplify the design of a product and success is achieved when a design is at its maximum simplicity.
• Occam’s (or Ockham's) Razor: A 14th century theory that states that in a series of hypotheses, the simplest one is most likely to be correct unless the burden of proof rests on a more complicated theory.