Before joining Hoffman Angeli LLP, Ms. Riordan served for several years as a judicial law clerk, first with Judge Melvin Brunetti at the U.S. Court of Appeals for the Ninth Circuit and then with Chief Judge Ancer L. Haggerty at the United States District Court for the District of Oregon.

A native Oregonian, Ms. Riordan received her bachelor's degree, magna cum laude, from the University of Oregon and her law degree from Berkeley Law School (Boalt Hall), where she worked with death penalty clients on post–conviction and direct appeals.

Ms. Riordan is a member of the Oregon State Bar, Federal Bar Association, Oregon Criminal Defense Lawyers Association, Gus J. Solomon Inn of Court, Multnomah County Bar Association and Oregon Women Lawyers. She is a member of the Boalt Hall Death Penalty Clinic Alumni Board and has served as an attorney coach for the mock trial and "We the People" teams at Reynolds High School in Portland.