The passage of the First Step Act (FSA) in Dec. 2018 ushered in the most extensive changes to the federal criminal justice system in decades. The authors describe long-standing impediments to providing strong continuity of care for inmates between the BOP and U.S. probation, describe in detail five FSA reentry provisions that currently challenge U.S. probation, and conclude with proposals to better ensure that the federal criminal justice system meets the legislative intent of the FSA.