Isabel F. Thelen

Isabel is a member of the firm's Professional Liability Department where she focuses her practice on the defense of a broad range of clients including attorneys, accountants, insurance producers, corporate directors and officers, and financial institutions. She has experience handling all stages of litigation, from pleadings and motion practice to discovery and settlement negotiations and has represented clients in complex commercial disputes, including actions in federal court as well as administrative proceedings.

Prior to joining Marshall Dennehey, Isabel worked as an associate at a New York law firm specializing in civil litigation, among other areas. She has also completed multiple legal internships and collaborated closely with attorneys during trial preparation in these roles.

Further, Isabel gained valuable litigation experience as a student attorney at the Glushko-Samuelson Intellectual Property Law Clinic of the American University Washington College of Law where she obtained her juris doctor degree. During law school, Isabel served as Associate Managing Editor for the American University Business Law Review. She holds a Bachelor of Arts degree in Global Commerce with a minor in Economics from Denison University.

Isabel is admitted to practice in the state of New York. Outside of work, she enjoys cooking, reading and listening to live music.

Associations & Memberships

New York State Bar Association

Year Joined

2025