Out of the running: Steyer ended his presidential bid on Feb. 29, following the South Carolina primary. He spent over $150 million of his own money on TV ads to boost his name recognition and get himself in front of voters in the four early voting states, but after disappointing finishes in the first three nominating contests -- in which he finished no higher than fifth place -- and despite an improved showing in the South Carolina primary, Steyer told supporters that he was ending his bid for the presidency because he didn't see a path where he could win.
Name: Tom Steyer
Date of birth: June 27, 1957
Hometown: Grew up in New York City but has lived in San Francisco since 1986
Family: Married to Kathryn "Kat" Taylor and they have four children
Education: He graduated from Yale and earned his MBA at Stanford University
What he does now: Before his presidential announcement, Steyer worked to gin up support for the impeachment of Trump, spending millions of dollars on a national ad campaign through the group NeedtoImpeach, which he founded and funds. He spent $120 million during the 2018 midterm elections in an effort to elect progressive candidates, turn out young voters and conjure support to begin impeachment proceedings.
What he used to do: Steyer left Wall Street for San Francisco in 1986 and began to manage a hedge fund, from which he built his wealth, according to his biography. The fund was made in coal mines and power plants in countries like China and Indonesia. In an interview on ABC's "This Week," Chief White House Correspondent Jonathan Karl pressed Steyer on his past investments in fossil fuels despite championing himself as an advocate for combating climate change.
"In our business, we invested in every part of the economy, including fossil fuels. When I realized what a threat this was ... to our environment, and to the people of the United States and people around the world. I changed, I divested from all of that stuff, I left my business, I took the giving pledge to give my money to good causes. And I'm asking every American to do exactly what I did," Steyer said.
Key life/career moments:
Through his organization NextGen America, Steyer organized, "the nation's largest voter-turnout effort" in the 2018 midterm elections, according to his biography. His work assisted in the Democratic party's majority taking over the House.
He stepped down as head of his investment firm in 2012 so that he could dedicate his time to philanthropy and political action, according to his campaign biography.
Where he stands on some of the issues:
One of Steyer's main focuses as president would be to combat climate change, according to a video announcing his candidacy. He said the country needs to address the fossil fuel companies that "dominate our politics" in order to reverse the effects of climate change. In 2014, Steyer funded $74 million into federal elections through a super pack he launched called NextGen Climate Action.
Steyer unveiled his "Five Rights" plan which aims to enable protections from big corporations their interests. His plan includes the right to an equal vote, the right to clean air and clean water, the right to learn, the right to a living wage and the right to health, according to his campaign website.
Another major policy focus Steyer announced is to remove corporate influence from politics.
"Americans are deeply disappointed and hurt by the way they're treated by what they think is the power elite in Washington D.C.," he said.
Steyer launched his presidential bid shortly after the second-quarter fundraising numbers were released. He has pledged to spend over $100 million of his own money towards his campaign.
In the first four weeks of his campaign, he outpaced every other candidate in his campaign ad blitz, scrambling to make up for lost time as he competes with rivals who are months ahead of him. Steyer has been blanketing airways and social media platforms in key states with advertisements targeting Trump and introducing himself to the American people. He's spent more than $6.6 million on television and online ads in the first four weeks of his campaign, according to television and online ad data. He has to -- the deadline to qualify for the third democratic debate in September is swiftly approaching and there's a high threshold for unique donors to qualify and candidates have to hit 2% in at least four recognized polls. In most of his online ads, he has asked donors to contribute $1 so that he could meet the donor count requirement and make it onto the stage in Houston.
What you may now know about him:
Steyer's father Roy served in the Navy and worked on the legal team that prosecuted Nazi war criminals after World War II in the Nuremberg Trials, according to his biography.
With his wife, he was among the first to sign the "giving pledge," a commitment to give away the bulk of their personal fortune during their lifetimes, his campaign website says.
ABC News' John Verhovek, Briana Stewart, Sasha Pezenik and Soo Rin Kim contributed to this report.