Should You Run More Than One Company? It may sound masochistic, but these founders have found success with parallel entrepreneurship.

Jaclyn Johnson didn't set out to run two startups at the same time. In fact, she never planned to launch one.

The first came from necessity. At 23, after an unexpected layoff, Johnson took on freelance marketing projects to pay her bills. When her workload got big enough, she formed No Subject marketing agency, counting L'Oréal and Microsoft as clients. And there it was: company #1.

That created another necessity. As a first-time founder, Johnson craved connection with other young women entrepreneurs, so she started organizing small gatherings in Los Angeles where female founders could talk frankly about their businesses and share and seek advice. She called the meetings Create & Cultivate, and the demand grew rapidly. "Brands were emailing me asking when the next one was and when tickets were going on sale," she said. So she created company #2: Create & Cultivate became official, and today it attracts big-name speakers, from Chrissy Teigen to Gloria Steinem. "I was working 120 hours a week," she said. "I was a full-blown masochist. But I was genuinely excited about both companies."