At FDA, Tom held senior leadership positions within the Office of Compliance in the Center for Drug Evaluation and Research (CDER), including leading the organization as Acting Director in 2016. Beginning in 2014, he led the Office of Manufacturing Quality (OMQ), where he was responsible for CDER’s enforcement activities covering current good manufacturing practice (CGMP) and drug quality. In this role, Tom was responsible for setting FDA’s CGMP enforcement priorities and for clearing warning letters, import alerts, and referrals for civil and criminal enforcement. He also played a central role in the FDA's deliberations concerning the approval of marketing applications submitted by companies with manufacturing compliance challenges.

As Acting Director of CDER Compliance in 2016, Tom oversaw OMQ as well as the offices responsible for enforcing FDA’s requirements for drug approval and labeling, human drug compounding, drug supply chain security and integrity, and clinical trials and bioequivalence studies.

He is a frequent speaker at conferences and trainings focused on drug quality, compliance, and enforcement at home and abroad.