One of the nation's top business regulators will be stepping down later this month to help companies navigate the complex legal issues surrounding privacy and data security.

Julie Brill, a commissioner at the Federal Trade Commission, will be heading into private practice at the law firm Hogan Lovells after her last day at the FTC, which is expected to be March 31.

Brill's nearly six-year tenure at the FTC has been marked by the independent agency's expanding interest in privacy issues, particularly in the technology industry. As one of five commissioners, Brill took a leading role in calling for greater scrutiny of data brokers — companies that trade in the commercial and behavioral information generated when consumers surf the Web or use their credit cards. She also pressed the FTC to look into how data can be used to marginalize vulnerable Americans, and played a role in hammering out a new U.S.-European agreement governing the flow of data across the Atlantic.

"[My experience] can really do a lot to help companies do the right thing: Understand this landscape and ultimately improve privacy practices and data-security practices," Brill said in an interview, "and continue the work that I'm doing at the FTC, but doing it on the ground, with companies."

Brill's term at the FTC would have expired later this year, in September. Her departure comes months after a fellow commissioner, Joshua Wright, stepped down to rejoin the academic world. The Obama administration has yet to nominate a successor for either position — and analysts say it is unlikely to happen before the election.

Brill is recognized by industry and policy leaders as a deft lawyer and a defender of consumers' rights. Rapid innovation, she said, has not only led to shifts in how consumers interact with their technology, but has also changed many industries' business models, with potentially dramatic if mostly invisible effects for the average consumer.

That lesson, together with an ability to develop strong interpersonal relationships with officials in industry and government, helped her succeed, said Microsoft's chief legal officer, Brad Smith.

"She combined a strong track record for consumers with a pragmatism that, in many ways, won over people in business," said Smith. "She leaves having contributed to a stronger reputation of the FTC."

Brill is leaving government at a time of uncertainty for thousands of businesses that depend on being able to move online data, such as Internet downloads and email, around the world instantly and easily. Last year, a European court struck down a 15-year-old transatlantic agreement that primarily aimed to protect the privacy of European citizens whose data is being handled by U.S. firms, such as Facebook, but which contained few restrictions on U.S. intelligence agencies looking for access to that data.

The end of that agreement, known as Safe Harbor, led to a rush by government officials to draft a replacement. Brill said she was "very involved" in the discussions that led to an agreement in February known as the E.U.-U.S. Privacy Shield. But even that compromise is likely to face substantial legal challenges, analysts say.

These and other upcoming court fights over data protection made Brill an attractive hire for a firm such as Hogan Lovells, said Jeffrey Chester, executive director of the consumer group Center for Digital Democracy.

"Julie Brill has been an extraordinary FTC commissioner who has played an important role supporting the strongest possible consumer protection," Chester said. "Hogan’s clients, and the industry, need someone like Julie who is respected by many powerful E.U. officials."

Brill joins a long line of FTC officials who have left public service to work on behalf of business. Mary Gardiner Jones, the agency's first female commissioner, stepped down in 1973 and two years later became an executive for consumer affairs at Western Union. Deborah Majoras, who chaired the agency from 2004 to 2008, became the general counsel at Procter and Gamble. Former FTC chairman Jon Leibowitz left the agency in 2013 and now advises corporate clients on mergers and acquisitions for the firm Davis Polk & Wardwell.

The so-called "revolving door" that sees government officials going into the private sector and vice versa has occasionally led to heightened scrutiny for the FTC. For example, while at the FTC, Wright recused himself from cases involving Google in order to allay any concerns about a potential conflict of interest stemming from Google's indirect financial support of his research at George Mason University. By helping companies sift through privacy and security law, Brill could become a highly influential adviser to some of the world's biggest technology firms.

Brill began her career clerking for a federal judge in Vermont and working at a law firm in New York. She later served the attorneys general of two states, Vermont and North Carolina. At the FTC, Brill has pushed the agency to hire more technologists who can help bring Washington up to speed on the latest in technology, as well as its potential risks and rewards for consumers.

Her departure, along with Wright's last August, means the FTC will now have only three members: Democratic chairwoman Edith Ramirez, Democratic commissioner Terrell McSweeny and Republican commissioner Maureen Ohlhausen.

It is unusual, but not unprecedented, for the agency to have so many of its senior posts unfilled, according to David Vladeck, a law professor at Georgetown University and a former director of the FTC's consumer protection bureau. But the agency, which acts as one of the nation's top privacy cops and antitrust enforcers, could be shorthanded for some time if Congress declines to confirm any nominees, as it is currently threatening to do with President Obama's nominee for the Supreme Court, Merrick Garland.

"Obviously the agency functions better at full strength," Vladeck said, "though I think that the agency is functioning quite well now."

Analysts believe the White House is unlikely to nominate a successor to Brill and Wright before the upcoming election, meaning that task may fall to the next president.