Castro teaches interactive storytelling, reporting, magazine publishing and media management, and is Medill's coordinator for the Carnegie-Knight News 21 journalism initiative.
Castro began her journalism career at Life magazine before becoming a longtime writer and editor for Time magazine, where she covered major policy issues, such as the American health care system. She went on to serve as managing editor of Time.com and editorial director of Britannica.com.
A founding editor of Discover magazine, Castro also is the author of The American Way of Health (Little Brown, 1994) and is a founding officer of the Online News Association. She is the former vice president of the Board of Governors for the Overseas Press Club of America.