Walker-Lightfoot worked at the SEC from 2001–06. While a lawyer in the SEC's Office of Compliance, Inspections and Examinations, she was tasked in 2003–04 with conducting the SEC’s investigation into a complaint about the activities of now-convicted Ponzi-schemer
Bernard Madoff and his firm. Walker-Lightfoot sent emails to her supervisor saying information provided by Madoff during her review didn't add up, and sent up a set of questions to ask Madoff's firm, according to a report in
The Washington Post. It is alleged that several of the questions alleged to have been raised directly challenged Madoff activities that turned out to be elements of his massive fraud, the newspaper said, however the SEC Inspector General’s report on the Madoff scandal notes that she was “the only person involved in the [SEC’s] Madoff examination to refuse to testify” to the OIG and it was therefore “difficult to assess her credibility” in making such claims. Madoff was sentenced to a prison term of 150 years on June 29, 2009, after he pleaded guilty to a decades-long fraud that U.S. prosecutors said drew in as much as $65 billion. Walker-Lightfoot left the SEC in January 2006, after having received a judgment in her favor against the SEC in a
hostile work environment case. Walker-Lightfoot did not experience a break in Federal service, as she immediately went to work at the
Federal Reserve Board of Governors, where she worked as a specialist in risk management and large financial institutions until October 2011. On November 16, 2009, Walker-Lightfoot was sworn into the Supreme Court of the United States bar. ==SEC leadership changes==