And following four years of light-touch regulation under Trump, Democrats are urging the SEC to step up oversight of major financial firms after a series of high-profile market snafus this year. In recent days, for example, international banks with operations in the U.S. suffered billions of dollars in losses after a little-known investment fund collapsed and sent shockwaves through the markets.

“Constant attempts by some of the industry to evade rules and regulations and a level playing field are in for a rude awakening from a Gary Gensler SEC,” said Better Markets President and CEO Dennis Kelleher, who served with Gensler on Biden’s presidential transition review team.

Biden’s selection of Gensler to lead one of the most powerful financial regulatory agencies in Washington has set up a host of potential clashes between the administration and Wall Street. While Biden ran as a moderate and enjoyed significant industry campaign support, Gensler’s nomination is a clear signal that progressive voices in the party are succeeding in a long-running push to rein in financial market excess.

“Mr. Gensler is an experienced public servant with a strong record of holding Wall Street accountable,” Senate Banking Chair Sherrod Brown (D-Ohio) said Tuesday. “He will lead the SEC at a time when it’s become more and more obvious to most people that the stock market is detached from the reality of working families’ lives.”

The Senate Wednesday approved Gensler for a term lasting until early June, though under SEC rules he would be able to serve through next year. Democrats plan to vote on another Gensler term that would allow him to stay in office into 2026.

Gensler, who also served in the Clinton Treasury Department, became an icon to Wall Street reformers when he led the CFTC under former President Barack Obama from 2009 to 2014.

While he first faced skepticism from the left because of his career at Goldman Sachs, Gensler emerged as one of the most aggressive financial market regulators in the wake of the 2008 meltdown as he implemented sweeping new safeguards on the trading of financial derivatives contracts.

At the helm of the SEC, Gensler is expected to strengthen the powerful agency’s enforcement efforts and pursue historic new rules related to climate change and digital currencies.

“We have seen that when the SEC does its job — when there are clear rules of the road and a cop on the beat to enforce them — our economy grows and our nation prospers,” Gensler told senators at his March confirmation hearing.

One of Gensler’s biggest challenges will be guiding the SEC’s efforts related to climate change, which is a top priority for the Biden administration.

The agency is at the heart of a growing push to police financial markets for climate risks because it can require companies to disclose their role in global warming and what kind of financial losses they may face from rising seas and other natural disasters.

Gensler told Sen. Elizabeth Warren (D-Mass.) at his confirmation hearing that companies “should not be able to hide” their climate risks from investors.

The agency under interim leadership this year has already taken steps in that direction, and the work will be able to accelerate once Gensler is in office. While some major companies such as Apple are beginning to back mandatory disclosure, it will no doubt be a huge lobbying battle as firms try to shape the rules and avoid legal liability for inaccurate reporting.

Democrats see a huge sense of urgency to act.

“Difficulty cannot be the reason why we slow down or stop,” SEC acting Chair Allison Herren Lee said last month. “We have to move ahead.”

But the SEC’s climate work will trigger major tensions between Gensler and congressional Republicans, who warn that the agency should stay out of climate policy and other social issues.

“I’m concerned he will cause the SEC to use its regulatory powers to advance a liberal social agenda focused on issues such as global warming, political spending disclosures, racial inequality and diversity,” said Sen. Pat Toomey of Pennsylvania, the top Republican on the Senate Banking Committee.

And while stocks have seen a steady rise over last year, the market in recent months has also experienced high-profile blowups that have raised fundamental questions about Wall Street risk taking and investor protection. The fallout will be front and center on Gensler’s agenda.

Gensler will likely face off with big banks over their entanglement in the Archegos Capital Management investment fund failure that rattled markets in recent days. The episode has exposed potential regulatory gaps, and Democrats want the SEC to investigate.

When leveraged financial bets by Archegos collapsed, the massive banks that did business with the fund scrambled to unwind their trading positions with the firm. It raised fresh questions about whether the banks were adequately protecting themselves — and the broader market — from risky activities that could trigger systemic risks.

Another episode of Wall Street turmoil that Gensler has pledged to untangle is the GameStop stock trading saga that unfolded in January, when a share-buying frenzy driven by social media forced online brokerages to halt trading.

The episode drew attention to the biggest upstart brokerage, Robinhood, and raised questions about whether it was giving users inappropriate incentives to trade.

It also attracted scrutiny to the relationships that Robinhood and other brokerages have with massive, high-speed trading firms that pay to execute orders made by the retail brokerages’ customers. Gensler has pledged to review the lucrative yet opaque financial arrangement at issue, known as payment for order flow, which critics say may not serve the best interests of individual investors.

In Senate testimony, Gensler warned that “a handful of financial firms are buying most of the retail flow in America.”

Lobbyists are also counting on Gensler to set overdue rules for the trading of cryptocurrency and other digital assets. Gensler is returning to government as an expert on the subject — he specialized in it at MIT.

“This is someone who can get a lot done,” said Chris Giancarlo, a former Republican CFTC chair. “He understands financial markets. He understands the complexity of financial markets, and at heart, he inherently believes in financial markets.”