JOAN LOUGHNANE is a global co-leader of Sidley’s White Collar Defense and Investigations practice. With 25 years of experience as a former federal prosecutor and defense attorney, Joan is a trusted advisor to companies, boards, and individuals facing high-stakes investigations and criminal and regulatory enforcement matters.
Joan represents clients across a broad array of industries, including financial services, fintech, life sciences, and technology companies. She handles sensitive investigations and complex enforcement actions by the United States Department of Justice (DOJ), the Securities and Exchange Commission (SEC), the New York Department of Financial Services (NYDFS), state attorneys general, and other federal and state regulators.
Joan is consistently recognized for her leadership, litigation experience, and public service. Recognized by Chambers USA for Litigation: White-Collar Crime & Government Investigations (2022–2025), clients report that Joan is “super smart and has incredibly good judgement” and is “thorough and responsive” (2025) and “experienced, connected, and strategic” (2024). Joan has also been recognized by Benchmark Litigation as one of its “Top 250 Women in Litigation” in the United States (2024–2025) and ranked in general commercial, securities, and white collar litigation (2020–2025). She was named to Crain’s New York Business’ 2024 “Notable Leaders in Accounting, Consulting and Law” list and its 2020 “Notable Women in Law” list.
Joan joined Sidley after serving in a series of leadership positions in the United States Attorney’s Office for the Southern District of New York, including Acting Deputy United States Attorney. In that role — the second highest in the office — she oversaw more than 200 prosecutors and lawyers in the office’s criminal and civil divisions, and acted as the office’s primary liaison to the Department of Justice’s leadership in Washington, numerous federal and state law enforcement agencies, and the United States District Court. Joan previously held a number of other senior leadership positions in the office, including Chief Counsel to the United States Attorney, Acting Chief of the Complex Frauds and Cybercrime Unit, Deputy Chief of the Criminal Division (during which time she was the office’s Project Safe Childhood coordinator, focusing on child exploitation issues) and Co-Chief of the General Crimes Unit. In 2018, Joan received the New York City Bar Association’s prestigious Henry L. Stimson Medal, awarded annually to outstanding Assistant U.S. Attorneys in the Southern and Eastern Districts of New York.
Prior to her supervisory roles, Joan spent the earlier part of her 15-year career as a federal prosecutor investigating and trying cases in a variety of the U.S. Attorney’s Office’s trial units, including the Securities and Commodities Fraud Task Force and the Violent Crimes Unit. In that time, she served as lead counsel on nine federal trials, and briefed and argued numerous cases in the United States Court of Appeals for the Second Circuit.
Joan began her legal career as a law clerk for United States District Judge Lewis A. Kaplan and spent three years as an associate at a well-known New York law firm.