Markkula was as instrumental in developing Apple as either of two Steves. He made an investment in Apple worth $250,000. In exchange for his investment, he took 30% of the company. He also helped manage the company, develop a business plan, hired the first CEO, and insisted Steve Wozniak join Apple. (At the time he was thinking about joining HP.)

Markkula was an early Intel employee and became a millionaire by the time he was thirty when the company went public. According to "Return to the Little Kingdom," his investment in Apple was less than 10% of his total worth at the time.

He stayed at Apple until 1997, overseeing the ouster and return of Steve Jobs. When Jobs came back, Markkula was left. He has since invested in a few startups and donated money to Santa Clara University, for the Markkula Center for Applied Ethics.