Polo's prime time debut was in TV 101. She also starred in the 1990 miniseries The Phantom of the Opera as Christine Daae. Polo played Detective Ash on the TV series Brimstone and became a regular cast member on the last season of Northern Exposure. She appeared in a recurring guest role in the sixth and seventh seasons of The West Wing playing the role of Helen Santos, the wife of Democratic presidential candidate Matt Santos (Jimmy Smits).

She also starred in the Lifetime Movie Network 2006 movie, Legacy of Fear. In 2009, she starred in the feature film 2:13 and the Hallmark Channel TV movie Expecting a Miracle with Jason Priestley and Cheech Marin. That same year she also starred in The Beacon (2009).

She was in the 2009 television pilot for Washington Field. The show was about the National Capital Response Squad, a unit of the FBI composed of elite experts in different areas who travel around the world, responding to events that concern American interest. In 2010, Polo reprised her role as Pam Focker in Little Fockers, the sequel to Meet the Parents (2000) and Meet the Fockers (2004).