About Us

Leadership Team

Chief Executive Officer, Dr. Kathleen O’Brien, Ph.D.
301-997-1300 ext 803

Kathleen O. O’Brien, Ph.D., is CEO of Walden/Sierra, Inc. a premier behavioral health organization serving Southern Maryland. She earned her Bachelor’s and Master’s degrees from the University of Maryland, and her doctorate in Clinical Psychology from LaSalle University.

Dr. O’Brien began her long association with Walden/Sierra in 1973, serving as the Clinical Director from 1978 to 1990, when she became the Executive Director. Her commitment and dedication have been a driving force in the development and expansion of a multi-service behavioral health organization that is respected throughout the State and has received national recognition.  Read More