Uber's first employee, who's now a billionaire, credits his success to this 1 tweet

Ryan Graves tweeted Uber co-founder Travis Kalanick a "tip" in 2010 — and nearly a decade later, became a billionaire.

The 35-year-old businessman, who's also the founder and CEO of Saltwater, reached out to Kalanick provided his email address after the billionaire businessman said he was looking for potential employees for a start-up company.

"Looking 4 entrepreneurial product mgr/biz-dev killer 4 a location-based service.. pre-launch, BIG equity, big peeps involved--ANY TIPS??" Kalanick asked in January 2010.

"Here's a tip. email me :) graves.ryan[at]gmail.com," Graves replied.

He became Uber's first official employee about two months later, on March 1. He joined the company's "core crew" which consisted of Kalanick, Oscar Salazar, Garrett Camp and one of Camp's close friends from graduate school.

In a December 2010 blog post, Kalanick said the team recognized Graves, who was working at General Electric at the time, was a "sharp guy" and agreed to interview him.

"Funny story how we brought him in. I was hitting Craigslist, Twitter, and other channels looking for the right candidate. What resulted was the Awesomest job post and response I’ve ever seen."

- Travis Kalanick

"Funny story how we brought him in. I was hitting Craigslist, Twitter, and other channels looking for the right candidate. What resulted was the Awesomest job post and response I’ve ever seen (I’m @konatbone)," Kalanick explained.

Graves hit the ground running, spending up to 20 hours a week with Kalanick going over business plans.

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"He learned the startup game fast and worked his a-- off to build the Uber team and make the San Francisco launch and subsequent growth a huge success. San Francisco launch day was May 31st, 2010 and the hair-on-fire craziness began," Kalanick continued.

Since then Graves has worn many hats within the company, briefly holding the title of CEO for a year in 2010 before transitioning to SVP of global operations. He resigned from the company in 2017 — shortly after Kalanick quit amid allegations that Uber’s workplace had a culture that failed to address sexual harassment and gender discrimination, as well as multiple other scandals — but remains on Uber's board of directors.

On Friday, the ride-sharing giant began public trading, with its initial public offering at $42 per share, a roughly $77 billion valuation. The first public trades were below Uber's initial $45 per share estimate, though it was still the largest IPO in recent history.

Graves' estimated net worth is now more than $1.4 billion, according to Forbes' real-time net worth data.

Graves tweeted a selfie outside of the New York Stock Exchange Friday to mark Uber's big moment.

According to Business Insider, Graves agreed to donate at least $14 million to charity after Uber went public.

Fox Business' Thomas Barrabi contributed to this report.