Drew HoustonREUTERS/Beck Diefenbach

Drew Houston is on top of the world.

On Friday, his company, Dropbox, filed its S-1, making it Y Combinator’s first startup to ever file for an IPO.

The file sharing service that began as a two-person team in 2007 is now a sprawling enterprise with more than a thousand employees and a stock ticker symbol that’s soon to be listed on the NASDAQ. The cloud storage giant now provides services to more than 500 million people and generates a billion dollars in annual revenue. 

But things weren’t always easy for Houston or his company. He struggled with his initial entrepreneurial venture and faced several obstacles getting Dropbox off the ground. Dropbox has taken 10 years of growth to get to the point it’s at now. 

But Houston hung in there. Despite multiple opportunities to sell his company in its early stages — including a bid from Steve Jobs in 2009 — he held on.

Here’s a rundown of Houston’s journey from a precocious tech-loving kid to the CEO of a billion-dollar enterprise: