At Princeton University, he served as the Robert E. Kahn Professor of Computer Science and Public Affairs, as well as being director of the Center for Information Technology Policy from 2007 to 2015 and from 2017 to 2019.

[3] In 2013, Felton was elected a member of the National Academy of Engineering for contributions to security of computer systems, and for impact on public policy.

Citing research he had undertaken with Christian Hicks and Peter Creath, two of his former students,[5] Felten testified that it was possible to remove Internet Explorer functionality from Windows without causing any problems with the operating system.

This led to a debate as to what exactly constitutes the "web browser," since much of the core functionality of Internet Explorer is stored in a shared dynamic-link library, accessible to any program running under Windows.

If the participants sent back the sample with the watermark removed (and with less than an acceptable amount of signal loss, though this condition was not stated by SDMI), they would win that particular challenge.

SDMI did not accept that Felten had successfully broken the watermark according to the rules of the contest, noting that there was a requirement for files to lose no sound quality.

SDMI claimed that the automated judging result was inconclusive, as a submission which simply wiped all the sounds off the file would have successfully removed the watermark but would not meet the quality requirement.

Planning to present the paper at the Fourth International Information Hiding Workshop of 2001 in Pittsburgh, Felten was threatened with legal action by SDMI,[6] the Recording Industry Association of America (RIAA), and Verance Corporation, under the terms of the DMCA, on the argument that one of the technologies his team had broken was currently in use in the market.

On November 15, 2005, Felten and J. Alex Halderman showed that Sony's method for removing XCP copy protection software from the computer makes it more vulnerable to attack, as it essentially installed a rootkit, in the form of an Active X control used by the uninstaller, and left it on the user's machine and set so as to allow any web page visited by the user to execute arbitrary code.

Felten and Halderman described the problem in a blog post: The consequences of the flaw are severe, it allows any Web page you visit to download, install, and run any code it likes on your computer.

"[12][13][14][15][16] In early 2008, New Jersey election officials announced that they planned to send one or more Sequoia Advantage voting machines to Ed Felten and Andrew Appel (also of Princeton University) for analysis.

"[22] In February 2008, Felten and his students were part of the team that discovered the cold boot attack, which allows someone with physical access to a computer to bypass operating system protections and extract the contents of its memory.

[23] In November 2010, Felten was named the first Chief Technologist of the Federal Trade Commission,[24] for which he took a one-year leave of absence from Princeton University.