The Tax Cuts and Jobs Act of 2017 overhauled the U.S. corporate tax system, lowering the statutory rate, exempting foreign earned income, and strengthening anti-abuse provisions. However, opportunities and incentives for abuse remain. Therefore, while developing tax policy is helpful, this paper posits that developing tax professionalism—not only tax policy—is needed. Efforts to reform tax policy should be balanced with efforts to develop and guard tax professionalism. Implementing tax policies in a flourishing tax system requires flourishing tax professionals. We develop theoretical and moral analyses to assess tax policy and tax professionalism approaches to tax reform. By targeting processes in the tax system, the tax policy approach attempts to influence practitioner behavior by restricting opportunities and incentives for corporate tax aggression. The tax professionalism approach recognizes that beneath efforts to influence behavior is a deeper, fundamental challenge to develop and protect tax professionals as reflexive agents capable of responsibly handling tax system opportunities and incentives. The tax professionalism approach focuses on persons in the tax system—not processes. This paper draws attention to the limitations of the tax policy approach and to the complementary need for the tax professionalism approach and proposes practical approaches to developing tax professionalism.