Which Apple co-founder designed the Apple I and Apple II computers?

Steve Wozniak designed the Apple I and was the primary designer of the Apple II.

Wozniak completed the basic Apple I design in early 1976, creating its hardware, circuit board, and operating system. Steve Jobs recognized that the machine could be sold and encouraged Wozniak to turn the design into a business venture, helping lead to Apple’s formation.

Wozniak then designed the Apple II, which Apple introduced at the 1977 West Coast Computer Faire. It became one of the first highly successful mass-produced personal computers, helped by features such as color graphics and built-in BASIC. Jobs contributed heavily to the product’s presentation and oversaw the development of its case, but the computer’s engineering design is chiefly associated with Wozniak.