David O’Neil is Co-Chair of the White Collar & Regulatory Defense Group and managing partner of the Washington, D.C. office.
Consistently recognized as one of the Nation’s top litigators and white collar defense attorneys, Mr. O’Neil represents companies and individuals in their highest stakes matters. His practice focuses on controversies that not only pose legal risk but also threaten political and reputational harm. He has represented the largest multinational companies and financial institutions, as well as CEOs, Board Chairs, Cabinet Secretaries, and world leaders. A former leader of the Criminal Division at the Department of Justice, Mr. O’Neil has tried numerous cases to verdict in federal court and argued six cases in the Supreme Court.
Many publications have recognized Mr. O’Neil’s litigation achievements. In 2024, he was named a finalist for The National Law Journal’s Attorney of the year and shortlisted for Global Investigations Review’s Investigations Professional of the Year. The American Lawyer has named him a “Litigator of the Year” finalist and featured him as a “Litigator of the Week” for a victory that The Washington Post hailed as “a win for democracy.” The National Law Journal recognized Mr. O’Neil twice as a Litigation Trailblazer, and Law360 named him as one of eight “White Collar MVPs” nationwide. He is ranked as a Band 1 lawyer for White Collar Crime & Government Investigations by Chambers USA (2026) where clients say he is “[o]ne of the finest lawyers I have ever worked with. David is a thoughtful, wise lawyer, a beautiful writer and a true champion of the client” and “David is a remarkable lawyer that is practical, thoughtful, has a nice way with clients and weighs risks exceedingly well. He is a fabulous white-collar attorney.”
Mr. O’Neil is also ranked as a leading lawyer in the Government Relations: Congressional Investigations and FCPA categories by Chambers USA (2026) where clients report, “David is a marquee name to call when you have a bet-the-company or bet-your-freedom matter” and “David's depth of experience, combined with his natural sharpness, make him an extraordinarily capable advocate and strategist.” He is also recognized as a Leading Partner for Corporate Investigations and White Collar Criminal Defense by The Legal 500 US (2025).
Prior to joining Debevoise in January 2015, Mr. O’Neil served for eight years in prominent positions within the Department of Justice. In early 2014, the President and Attorney General designated Mr. O’Neil to lead the Criminal Division, where he was responsible for supervising more than 600 attorneys investigating and prosecuting the full range of federal crimes, including corporate malfeasance, cybercrime, fraud offenses and money laundering. Mr. O'Neil also served as Deputy Assistant Attorney General for the Fraud Section. In that capacity, he supervised more than 100 prosecutors engaged in nationwide enforcement of the FCPA, healthcare fraud and securities and financial fraud.
Before moving to the Criminal Division, Mr. O’Neil served for three years as Senior Associate Deputy Attorney General and Chief of Staff to the Deputy Attorney General, the Department's second-in-command. In that role, he was part of DOJ’s core management team, with direct supervisory responsibility for more than two dozen attorneys. He was also an Assistant to the Solicitor General, authoring more than 50 briefs filed with the Supreme Court and handling appeals from high-profile white-collar criminal convictions.
Mr. O’Neil began his career at DOJ as a federal prosecutor in the U.S. Attorney’s Office for the Southern District of New York. As an Assistant U.S. Attorney, he tried numerous cases to successful jury verdicts and defended those verdicts on appeal.
Mr. O’Neil earned his J.D. magna cum laude in 2000 from Harvard Law School, where he was an editor of the Harvard Law Review. He graduated from Princeton University with a B.A. magna cum laude in 1995.
Upon graduation from law school, he clerked for two years, first for Judge Robert D. Sack of the U.S. Court of Appeals for the Second Circuit and then for U.S. Supreme Court Justice Ruth Bader Ginsburg.
David A. O’Neil 律师是诉讼业务合伙人，以及本所白领犯罪和合规辩护部门成员。他受到《美国钱伯斯》（2022年）和《美国法律500强》（2022年）的推荐，被评为“白领犯罪和政府调查”以及“国际诉讼”领域的杰出律师。O’Neil律师的执业领域主要为白领犯罪辩护、内部调查、反腐败与FCPA辩护以及国会调查。他在2018和2020年均被《国家法律期刊》（National Law Journal）评为“诉讼领域之先驱”，在2018年被《法律360》评为“白领犯罪领域最具价值律师”。客户在《美国钱伯斯》（2022年）中称赞O’Neil律师一位“具有经验和技术知识的非凡律师”，是“才华横溢的律师、无畏的战略家和杰出的领导者的罕见而有价值的结合。”，并表示他“主动”，“务实”，“反应迅速，思维敏捷。”O’Neil律师还获得《拉美法律500强》（2022年）在合规与调查领域的推荐。
O’Neil律师执业的一个特点在于他专注于代表客户处理涉及重大的法律、政治和公共关系影响的高风险事务，包括美国司法部及海外执法机构的刑事调查；知名公司的敏感而机密的内部调查；美国国会调查；由州司法部长提起的诉讼以及集团诉讼。
在2015年1月加入德普前，O’Neil律师曾在司法部担任要职八年。2014年上半年，美国总统和司法部长官任命O’Neil律师担任犯罪部门负责人，负责监督超过600名检察官调查并起诉各种联邦犯罪，包括公司渎职、网络犯罪、欺诈和洗钱。O’Neil律师还曾担任欺诈部门的副助理司法部长。在担任该职务期间，他曾监督超过100名检察官处理全国范围内的《海外反腐败法》（FCPA）执法、医疗欺诈，以及证券金融诈骗。
在调任犯罪部门前，O’Neil律师曾在三年内担任高级助理副司法部长、副司法部长首席工作人员、部门二把手。在担任此职位期间，他作为司法部核心管理团队，直接监督超过二十名检察官。他还参与处理了大量要案，包括重要的FCPA案件公诉、有关伦敦银行同业拆借利率调查、有关洗钱和违反《银行保密法》的对金融机构的大型调查。
2009年，O’Neil律师担任联邦总律师助理。他曾在美国最高法院的三起案件中进行辩论，起草超过50份提交最高法院的诉状，并处理大型白领犯罪案件定罪引发的上诉。
O’Neil律师在司法部的职业生涯起始于担任纽约南区联邦检察院检察官。作为一名助理联邦检察官，他曾参与众多案件获得胜诉陪审团裁决，并参与数起上诉案件的辩论。他曾处理多起涉及金融机构的案件，包括银行欺诈、按揭和身份窃取问题。
O’Neil律师于2000年作为优等生从哈佛法学院取得法律博士学位，他曾在《哈佛法律评论》担任编辑。他于1995年作为优等生毕业于普林斯顿大学，获得文学学士学位。
从法学院毕业后，他曾在两年期间担任美国联邦第二巡回法院上诉法院Robert D. Sack法官书记员，后曾担任美国最高法院Ruth Bader Ginsburg法官的书记员。