A Republican, Barry was nominated to serve on the United States Court of Appeals for the Third Circuit by Democratic President Bill Clinton on June 17, 1999.
She was nominated to fill the vacancy created when H. Lee Sarokin retired in 1996. (
Clinton had nominated Robert Raymar to the seat in 1998, but that nomination had expired at the end of the year without being given a hearing by the Senate Judiciary Committee.)

The Senate unanimously confirmed Barry on September 13, 1999.
She received her commission on September 22, 1999. "
I am deeply honored and very grateful for the nomination," Barry told the New Jersey Law Journal in 1999. "
I am surprised I was approached on it.
I assume that my record is good enough as a district court judge to be reached out to, and I'm glad that politics weren't a priority here."

In January 2006, Barry testified in support of the appointment of fellow Third Circuit Judge Samuel Alito to the Supreme Court.

In a 2006 ruling, Abou Cham v. Attorney General, Barry was harshly critical of the conduct of a U.S. Immigration Court judge in a case involving a refugee from The Gambia.
The refugee petitioner was the nephew of former Gambian president Dawda Jawara, who had been deposed in a coup in 1994; the new regime had imprisoned or killed several of Cham's relatives, and outlawed their political party.
Barry ruled in favor of Abou Cham; criticized Judge Ferlise's questioning over a two-day hearing as bullying, belligerent, and abusive toward "an increasingly distraught petitioner"; and concluding that Cham had been "ground to bits" emotionally.
Barry wrote that there was "not a modicum of courtesy, of respect or of any pretense of fairness" in Ferlise's treatment of Cham, which led Ferliste to conclude that Cham's testimony was not credible, and concluded that the Immigration Court's ruling was a "severe wound" on the American justice system.
Ferlise was relieved of his duties shortly after Barry's decision.

On June 30, 2011, Barry assumed senior status.
She took inactive senior status in the first week of February 2017, about two weeks after her brother's inauguration as president.

Barry retired on February 11, 2019.
Her retirement brought an end to an investigation of whether she had engaged in fraudulent tax schemes with her siblings that violated judicial conduct rules.
The investigation closed without reaching a conclusion about the allegations.
A Republican, Barry was nominated to serve on the United States Court of Appeals for the Third Circuit by Democratic President Bill Clinton on June 17, 1999. She was nominated to fill the vacancy created when H. Lee Sarokin retired in 1996. (Clinton had nominated Robert Raymar to the seat in 1998, but that nomination had expired at the end of the year without being given a hearing by the Senate Judiciary Committee.) 
The Senate unanimously confirmed Barry on September 13, 1999. She received her commission on September 22, 1999. "I am deeply honored and very grateful for the nomination," Barry told the New Jersey Law Journal in 1999. "I am surprised I was approached on it. I assume that my record is good enough as a district court judge to be reached out to, and I'm glad that politics weren't a priority here."
In January 2006, Barry testified in support of the appointment of fellow Third Circuit Judge Samuel Alito to the Supreme Court.
In a 2006 ruling, Abou Cham v. Attorney General, Barry was harshly critical of the conduct of a U.S. Immigration Court judge in a case involving a refugee from The Gambia. The refugee petitioner was the nephew of former Gambian president Dawda Jawara, who had been deposed in a coup in 1994; the new regime had imprisoned or killed several of Cham's relatives, and outlawed their political party. Barry ruled in favor of Abou Cham; criticized Judge Ferlise's questioning over a two-day hearing as bullying, belligerent, and abusive toward "an increasingly distraught petitioner"; and concluding that Cham had been "ground to bits" emotionally. Barry wrote that there was "not a modicum of courtesy, of respect or of any pretense of fairness" in Ferlise's treatment of Cham, which led Ferliste to conclude that Cham's testimony was not credible, and concluded that the Immigration Court's ruling was a "severe wound" on the American justice system. Ferlise was relieved of his duties shortly after Barry's decision.
On June 30, 2011, Barry assumed senior status. She took inactive senior status in the first week of February 2017, about two weeks after her brother's inauguration as president.
Barry retired on February 11, 2019. Her retirement brought an end to an investigation of whether she had engaged in fraudulent tax schemes with her siblings that violated judicial conduct rules. The investigation closed without reaching a conclusion about the allegations.
Maryanne Trump Barry