Marielle C. Montecillo

426 W. Lancaster Avenue, Suite 200
Devon, PA 19333

Office: (267) 930-4675


Villanova University Charles Widger School of Law
Juris Doctor, 2020

Seton Hall University School of Diplomacy and International Relations
Bachelor of Science, Diplomacy & International Relations and Economics, 2017, cum laude


  • Pennsylvania

Practice Areas

Marielle Montecillo is an Associate at Mullen Coughlin and assists clients with investigating and responding to data privacy and security incidents. After an incident, such as a data breach, has been identified, Marielle works closely with the organization in determining the nature and scope of the incident and coordinates with forensic investigators, law enforcement, regulatory agencies and other third-parties to ensure that the incident is fully investigated and day-to-day business is minimally interrupted. She also counsels clients on their legal and regulatory obligations and works to ensure that they are compliant with all respective laws, statutes and industry standards or requirements.

Ms. Montecillo joins Mullen Coughlin from a top-rated public accounting firm where she was a Tax Associate. There, she researched and wrote on various tax issues related to state and local tax and mergers and acquisitions.

While a law student at Villanova University, Marielle was in the “Student Honors Program” in the U.S. Securities and Exchange Commission’s (SEC) Division of Enforcement. While with the SEC, Marielle investigated enforcement leads through a variety of sources and also assisted in the litigation of enforcement actions by drafting legal memos, conducting legal research and attending confidential meetings and depositions.

Marielle was also the Managing Editor of Citations & Sources for Villinova’s Jeffrey S. Moorad Sports Law Journal.