The bookkeeper at the first McDonald's started working for free! What was her net worth 10 years later?

A woman named June Martino will always be remembered as an influential personality in the history of McDonald's. She became the bookkeeper for Ray Kroc, the founder of McDonald's, but eventually worked her way up and became a part owner of the corporation.

According to Ray, "She had a presence that conveyed integrity and a restless native ability to deal with problems. This was enveloped in a warm, compassionate personality, a rare combination of traits. The fact that she had no bookkeeping experience bothered me not at all. I knew she would master the technical routines quickly."

In 1955, she began working at the first McDonald's in Des Plaines, Illinois. Later, she would serve as a "talent scout" for the company, helping shape it into what it is today.

McDonald's went public in 1965. Ray Kroc, in gratitude for her long hours and hard work with little pay in the early years, rewarded her with an equity interest in the company. So, June cashed out $300,000 in 1965—that's the equivalent of 1.7 million in today's dollars. Her remaining holdings were worth 5 million dollars (I.e. $28 million when adjusted for inflation).

In the case of June Martino, hard work really did pay off.

(Source)