Wynn-Williams practiced law at the
Mallesons, Stephen, Jacques law firm. From 2002 to 2007, she was a policy adviser in the
diplomatic service of the New Zealand government. From 2007–2011, she managed New Zealand's political affairs and government relations office at its
embassy in Washington, D.C. She has also worked for
Oxfam International. Wynn-Williams began working for Facebook in 2011, eventually becoming its global
public policy director. Facebook terminated Williams's employment in 2017, allegedly for "poor performance and toxic behavior". Williams has stated she believes this was in retaliation for reporting her boss
Joel Kaplan for
sexual harassment.
Careless People: A Cautionary Tale of Power, Greed, and Lost Idealism In 2025, she released
Careless People: A Cautionary Tale of Power, Greed, and Lost Idealism, a book about her career at Facebook. The book's most significant revelations were an alleged “lethal carelessness” around ethical choices such as that Meta worked with the Chinese Communist Party to spec and build censorship tools that worked with China's
Great Firewall, and insights into Mark Zuckerberg's attitudes around international public policy during her tenure. Facebook threatened legal action and an
arbitrator prohibited Wynn-Williams from promoting the book. Facebook is attempting to enforce a non-disparagement agreement. In September 2025, British politician
Louise Haigh stated that Meta is attempting to fine Wynn-Williams $50,000 for every breach of the non-disparagement order. Facebook/
Meta has argued that the book is "out of date" and does not reflect current practices. In their review of the book,
The Guardian's Stuart Jeffries said that Wynn-Williams' retelling of her time at Facebook had "cult vibes" and involves strong criticism of
internet.org and Facebook's corporate leadership. Sabhanaz Rashid Diya, a former head of public policy for Meta in Bangladesh who did not work for the company at the same time as Wynn-Williams, described the book as "a courageous feat, but it glosses over [Wynn-Williams's] own indifference to warnings from policymakers, civil society, and internal teams outside the U.S. about serious harm to communities from Facebook." Wynn-Williams testified about Facebook/Meta before the
Senate Judiciary Committee on April 9, 2025. == Personal life ==