From an NBC press release:
MARY MCCORMACK (‘K STREET’) MOVES UP TO PENNSYLVANIA AVENUE WHEN SHE GUEST-STARS ON NBC’S ‘THE WEST WING’ AS PRESIDENT’S NEW DEPUTY NATIONAL SECURITY ADVISER
BURBANK – March 29, 2004 – Mary McCormack (“K Street,” “Private Parts”) will guest-star on a four episode arc on NBC’s Emmy Award-winning “The West Wing” (Wednesdays, 9-10 p.m. ET) as the President’s (Martin Sheen) new deputy National Security Adviser whose first encounter with the Chief Executive proves to be more brusque than she expected.
McCormack’s first episode, “The Promise,” will be broadcast later this spring. In the storyline, she plays Kate Harper, a U.S. Naval Academy graduate and military prodigy who is not afraid to stay true to her advice and convictions.