Dr. Scott Gottlieb plans to work on drug prices and other health policy issues as a part-time fellow at the American Enterprise Institute, after he leaves his post as commissioner of the Food and Drug Administration.

His last day at the F.D.A. is Friday. In an interview, Dr. Gottlieb said he was not yet sure what other work he would pursue beyond the half-dozen or so days he’d spend each month at the conservative think tank. Although A.E.I., where Dr. Gottlieb once worked, opposed some regulations of vaping, it did not take part in the vituperative public attacks on Dr. Gottlieb for his work to end the youth vaping epidemic like much of the rest of the Washington conservative establishment.

Dr. Gottlieb took office in May 2017, and was best known for his aggressive drive to regulate the tobacco and e-cigarette industries. But he also ventured beyond the typical regulatory boundaries for an F.D.A. chief, frequently criticizing the prescription drug industry for high prices and accusing some pharmaceutical businesses of gaming the system to avoid the competition that would lower them.

A prolific writer of op-eds, Dr. Gottlieb said he would focus on some of the structures in the Medicare program that inhibit competition.