Gross Domestic Product's (GDP) limitations as a prosperity indicator are now widely recognized, leading to a search for "beyond-GDP" alternatives. The US state of Maryland has calculated one such alternative, the Genuine Progress Indicator (GPI), since 2010. What effect is Maryland's GPI having in practice? Is there any evidence to date that the GPI has shaped policy and public priorities in ways that live up to its supporters' hopes-whether for a transformative shift beyond the economic-growth paradigm or simply better policymaking? What key obstacles exist to fulfilling those goals? This article draws on semi-structured interviews with elite respondents-including Maryland's former governor, senior public servants, academics, non-governmental organization employees and foundation leaders-involved in producing, advocating and using the GPI, along with analysis of relevant documents. Although significant impacts on policy are not yet evident and a change of governor has removed high-level support, the GPI initiative has revealed innovative possibilities for more environmentally and socially minded policymaking and introduced new ideas with potential long-term impacts. However, various challenges remain, including strengthening the political constituency behind the GPI, more deeply embedding it into the policymaking process and addressing the GPI's own limitations in supporting a beyond-GDP economic narrative.