Ryan Graves’ career at Uber began with a tweet.

In January 2010, when Uber was less than a year old, Travis Kalanick, then the CEO, tweeted: “Looking 4 entrepreneurial product mgr/biz-dev killer 4 a location based service.. pre-launch, BIG equity, big peeps involved-ANY TIPS??”

Graves saw Kalanick’s tweet and responded: “Here’s a tip. email me :)”. He included his email address, too.

Graves stepped down from Uber on Thursday, but his unconventional job application led him to one of the longest-running tenures at Uber – he even outlasted Kalanick, who resigned as CEO earlier this year.

Graves most recently served as the company’s senior vice president of global operations, but he held several positions at Uber, even briefly serving as CEO before handing the reins back to Kalanick in 2011.

"Ryan Graves' first day was March 1st and he hit the ground running," Kalanick wrote in a blog post detailing Uber's origins. "From the day he got going, we spent about 15-20 hours a week working together going over product, driver on-boarding, pricing model, the whole nine. He learned the startup game fast and worked his ass off to build the Uber team and make the San Francisco launch and subsequent growth a huge success."

From working for free to $1.58 billion

In 2010, Graves' work experience included a database-administrator position at General Electric and a stint in business development at Foursquare, which he acquired by working for the company for free after it initially turned him down.

Kalanick presumably followed up with Graves after his initial tweet, and Graves became Uber's first hire. Graves was known throughout his time at Uber as the "Mr. Nice Guy" in contrast with Kalanick's aggressive personality, and he was said to be well-liked by his peers both within Uber and the larger tech community.

Chris Sacca, an early investor in Uber, wrote several glowing tweets about Graves on Thursday after the news of Graves stepping down. Graves and Sacca are longtime friends - Graves and his wife even spent the night at Sacca's house before Graves started at Uber.

Graves is "the director most consistently respected by the others and is great at building consensus," Sacca wrote.

https://twitter.com/sacca/status/895696208219353088

Kevin Rose, an investor, also tweeted his support:

Graves has been noticeably absent throughout Uber's tumultuous past six months. He transitioned to a new "resident builder and entrepreneur" role last year, and multiple people told Business Insider in March that Graves wasn't often seen around the office for long stretches of time and seemingly had a decreased role in the company.

Graves wrote in an internal memo obtained by Business Insider that he would officially leave the company in mid-September but remain involved with the hunt for Uber's new CEO.

These days, Uber's $68 billion valuation makes Graves a paper billionaire. While cofounders Kalanick and Garrett Camp have a larger stake in the company than Graves does, Graves is worth $1.58 billion, according to Forbes.

Maya Kosoff contributed to an earlier version of this story.