I helped Mark Zuckerberg start Facebook and now I'm the CEO of Philo. Here's a day in my life in San Francisco balancing work and kids.

Jason Henry for BI

This as-told-to essay is based on a conversation with Andrew McCollum, the 42-year-old CEO of Philo, based in San Francisco. It's been edited for length and clarity.

My first job was at Subway, but my first meaningful career job was helping to start Facebook during my time at Harvard.

I spent a lot of time with Mark Zuckerberg, Dustin Moskovitz, Chris Hughes, and the other founders of the company. We worked together on various things and discussed ideas for projects we thought were cool.