Sarah Cave, a securities and bankruptcy litigation partner at Hughes Hubbard & Reed, has become an “immigration guru,” according to Heidi Lee Henderson, senior director of legal services at inMotion, whose cases Cave has handled pro bono for the past six years.

Cave, 38, was first introduced to pro bono immigration work as a first-year associate in 1998. The University of Michigan Law School graduate said she fell in love with the work, which she said combines challenging legal issues with compelling human stories.

“In many cases, literally people fled for their lives, left everything they had, showed up at the doorstep of the U.S. and hoped they’d be allowed to stay,” Cave said. “Why wouldn’t you help?”

Since 2009, Cave has averaged more than 260 pro bono hours annually, primarily focusing on deportation, asylum and other immigration-related cases. In 2011 alone, she spent 330 hours on pro bono matters on top of completing 2,056 hours of billable work in securities and bankruptcy litigation.

Cave has been involved in some of the most high-profile securities matters in the last decade, including those involving Bernard Madoff, WorldCom, Tyco, Global Crossing and Priceline. She is also on the team representing the trustee liquidating the broker-dealer arms of both Lehman Brothers and MF Global in Securities Investor Protection Act liquidation proceedings.

Cave’s corporate clients include both foreign and domestic financial institutions, accounting firms, professional services firms and individuals who find themselves involved in securities litigation, regulatory proceedings or criminal enforcement investigations. She is in court at least a few times each month.

In spite of the high-pressure and demanding nature of her practice, Cave has found time to develop an additional expertise in immigration law and devote significant hours to individual pro bono cases and recruiting others to the cause.

For the past three years she has served as co-chair of Hughes Hubbard’s pro bono committee. The firm has been recognized as a leader in pro bono, ranking second in the country in The American Lawyer‘s Pro Bono Survey in 2011. That year, Hughes Hubbard’s 300 lawyers logged 47,000 pro bono hours, with more than 70 percent of the firm’s attorneys dedicating 20 hours or more.

“Every single thing we do [in pro bono] she has a hand in,” said Candace Beinecke, chair of Hughes Hubbard. She estimated that Cave spends at least an additional 200 hours each year on the administrative duties, developing and supervising the firm’s pro bono program.

“She does about everything one can expect of someone in her position and three times more,” Beinecke said.

Cave has personally handled about 13 cases for inMotion—which provides free legal assistance to low income women, many of them victims of domestic violence—and has recruited more than 90 attorneys and staff from Hughes Hubbard to take on matters for the group, said Henderson.

Among Cave’s inMotion clients was an undocumented woman from the Dominican Republic who was abused by her husband. With Cave’s help, the woman successfully filed a Violence Against Women Act petition and obtained legal permanent residency, which allowed her to travel to the Dominican Republic to reunite with her daughter, whom she had not seen in 10 years.

“Sarah goes above and beyond what lawyers normally do on cases,” said inMotion’s Henderson, adding that the group honored Cave with an award for her work on the case. “She’s been a real cheerleader and supporter of the work and mission and really cares about doing the right thing.”

Cave also has remained involved in the case of a woman from Mali who came to the U.S. on a visitor’s visa in 2000 and is seeking asylum. The woman underwent genital mutilation and could be forced to marry her cousin if she returns to Mali. She also has two children who are U.S. citizens and does not want to leave.

Cave took on the case five years ago after an immigration judge rejected the woman’s claims. That decision was upheld by the Board of Immigration Appeals. Then-U.S. Attorney General Michael Mukasey reviewed the matter, vacated the board’s decision and remanded the case for additional fact finding.

While the woman is safe in the United States, her attorneys are pushing for an asylum claim to provide permanent protection.

Natalie Nanasi, director of the Domestic Violence Clinic at American University Washington College of Law, called Cave’s “devotion and commitment” to this client “impressive.”

“There are a lot of cooks that have been in this kitchen and not many have stayed throughout the long-term,” said Nanasi, who worked with Cave through Tahiri, an immigration legal services organization in Virginia.

While many attorneys got involved when the attorney general did and it was “sexy,” Nanasi said, Cave was one of the few who wasn’t too busy when it came time to do the work.

Cave also has worked closely with the Legal Aid Society, taking on difficult removal cases. This includes representing immigrants with AIDS or other diseases, where deportation may be tantamount to a death sentence if treatment is not available in their home country.

“It’s messy work,” said Marlene Halpern, supervising attorney for pro bono at Legal Aid, adding that it is often difficult to find attorneys willing to take on these lengthy, complicated cases.

“If I said to my immigration practice here that Sarah is available, they are all jumping for joy,” Halpern said.

Cave, who has received a number of awards from Legal Aid, coordinates a group from Hughes Hubbard that staffs Legal Aid’s immigration hotline, which is available to detainees and their families seeking information, advice or representation.

“The immigration process is a really scary thing to try to navigate on your own,” Cave said. “For people who come here looking to be able to stay and be safe and live here as citizens, that’s something we should encourage, not discourage.”

She admits the work is challenging, and it is often difficult to locate documentation and other evidence to support an immigrant’s case, as some clients leave home with nothing but the clothes on their backs.

The greater difficulty, Cave said, is dealing with a legal system that can be biased against her clients.

“The deck is stacked against people who are not as sophisticated or don’t have the education or financial resources to make their way through the system,” she said. “Just having a big law firm on their side goes a long way.”

Having Cave on his side helped Cameroon refugee Prosper Walter Noupayo win asylum after he was beaten and tortured by Cameroon government security for participating in a political party opposed to the country’s president.

And in a non-immigration matter, Cave persuaded the U.S. Court of Appeals for the Second Circuit to allow Ruddy Quezada to file a second habeas corpus petition, asserting that the state used perjured testimony to secure his 1993 second-degree murder conviction. That petition is pending.

“The difference between a positive result and negative result is often the presence of a lawyer,” Cave said. “Making sure even those who can’t afford it get the best representation is essential to the system working properly.”