Internationally known pro bono attorney Stephen Oleskey advised the graduates of Northeastern University School of Law to use the law to create needed change.

Speaking at the law school commencement ceremony in the Cabot Center on Friday, Oleskey said, “You will find the next decade a time that will present you with great fulfillment in law. It will be a time to tap into the world of law and work to change what you feel must be changed.”

Oleskey, a senior partner at the Boston law firm WilmerHale and co-lead counsel on a habeas corpus suit challenging the imprisonment of six Algerians at Guantánamo Bay, described the five-year effort, which ultimately involved nine partners contributing an estimated $20 million worth of legal work, as one of his most fulfilling experiences as an attorney.

Last year the U.S. Supreme Court announced its decision in Oleskey’s case, Boumediene v. Bush, ruling that the detainees are entitled to the right of habeas corpus. On May 15, the lead petitioner in the case was released from Guantánamo after spending nearly seven-and-a-half years in detainment.

Oleskey has spent the past 40 years engaged in public-service legal work. A former Massachusetts deputy attorney general and past chief of the state’s Public Protection Bureau, he is now a member of WilmerHale’s commercial litigation practice group.

He said he feels a special affinity for Northeastern law school and its commitment to human rights law, noting that his late father-in-law graduated from the law school.

Law school dean Emily Spieler described Oleskey as an elegant, effective and fearless litigator. President Joseph Aoun presented him with an honorary Doctor of Laws degree.

The importance of pro bono work was also the theme of the faculty address by law professor and former law school dean David Hall.

Among the values Hall said he shares with the graduates are that lawyers are more than “hired guns” and that pro bono work is a cherished, sacred ideal. He urged students to hang onto the beliefs and ideals they learned here. “Northeastern has given you a platform with which you can change the world,” Hall said.

Hall, who has spent 24 years at Northeastern, became the first African-American dean of the law school in 1993. Five years later, he was named provost of the university, a position he held until 2003.

As he prepares to leave Northeastern to become president of the University of the Virgin Islands, the address was especially poignant for him, he said.

“We may never visit it again, but the insights and values we have gained at Northeastern Law will always be with us,” Hall said. “Now it’s a part of your DNA and mine as well.”

Hall also encouraged the graduates to face the troubled economy head-on. “It is not the struggle in our lives that breaks us,” he said. “It is the life where there is no meaning that breaks us.”

In her remarks to students, Spieler struck an optimistic note.

“Despite the challenges of the world, this is a time for us to celebrate the important moment in your lives. As new lawyers, we train in an important profession,” she said. “Never, ever be afraid to speak truth to power.”

President Aoun wrapped up the ceremony by urging the graduates to constantly challenge their own thinking. “Question your certainty,” said Aoun. “Use your legal training to challenge your own assumptions. Never assume that you have all of the answers.”