 She serves on the Council of the American Law Institute.On April 14, 2016, President Obama nominated O'Sullivan to serve as a United States District Judge of the United States District Court for the Western District of Washington, to the seat vacated by Judge Marsha J. Pechman, who took senior status on February 6, 2016.That nomination expired on January 3, 2017, with the end of the 114th Congress.