Julia Hartz, 35
Next year marks a decade since Eventbrite was formed—and, coincidentally, the 10-year wedding anniversary of Hartz and her co-founder/husband, Kevin. While her significant other has the CEO role, it’s Hartz who has become the internal and external face of the online ticketing platform, now said to be worth more than $1 billion. In addition to advising marketing, PR and customer relations, the former MTV exec spends about one-third of her time on recruiting efforts. The company’s service is now used to organize, promote and sell 8 million tickets per month for a wide range of events—from San Francisco-based indie music shows to Pope Francis’s speech in Philadelphia. But Hartz says her biggest accomplishment is maintaining Eventbrite’s culture even as it has grown (the company recently made Fortune’s 100 Best Workplaces for Millennials list, see company profile here).