Judge Diarmuid O’ Scannlain is a 34-year veteran of the U.S. Court of Appeals for the Ninth Circuit. He was appointed by President Reagan in 1986. As a judge on the U.S. Court of Appeals for the Ninth Circuit, Judge O’Scannlain has participated in over 11,000 federal cases and has written hundreds of published opinions on a broad range of subjects including constitutional law, international law, securities law, administrative law, and criminal law. The late Chief Justice Rehnquist appointed Judge O’Scannlain to the Federal Judicial Center’s Advisory Committee on Appellate Judge Education. In 2009, Chief Justice Roberts appointed Judge O’Scannlain to the International Judicial Relations Committee of the U.S. Judicial Conference and subsequently appointed him Chairman in 2010. In 2017, he assumed senior status.

Judge O’Scannlain received a J.D degree in 1963 from Harvard Law School. He graduated with his undergraduate degree from St. John’s University. He also earned an LL.M degree at University of Virginia law School. Judge O’Scannlain holds three honorary doctorate degrees: an LL.D. (honoris causa) degree from the University of Notre Dame in 2002, an LL.D. (honoris causa) degree from Lewis & Clark College in 2003 and the LL.D. (honoris causa) degree from the University of Portland in 2011. Judge O’Scannlain is an adjunct professor at Lewis & Clark Law School and teaches at numerous federal appellate seminars for judges and attorneys.

Judge O’Scannlain, a first generation Irish-American son of immigrant parents from Sligo and Derry, is married to Maura Nolan and has eight children: Sean, Jane, Brendan, Kevin, Megan, Christopher, Anne, and Kate and nineteen grandchildren. His chambers are in the Pioneer Courthouse in Portland, Oregon.