The vehicle-to-grid (V2G) innovation—which enables electric vehicles to return stored electricity to the grid—holds significant potential to support renewable energy integration and electric vehicle adoption. Despite growing interest in V2G, there is still limited understanding of user preferences and the factors influencing decision-making. To explore this, we conducted a stated intention study with 1018 participants, examining their likelihood of participating, and their primary drivers and barriers. Our analysis—using a random parameters order probit model and mixed logit models—revealed that most respondents were likely to participate (42%) or remained neutral (32%). Financial incentives were the primary driver (49%), followed by electricity grid-stability (26%) and environmental (25%) factors. The main barrier for most was loss of flexibility (55%), followed by battery degradation (27%) and data concerns (18%). The study highlights how user characteristics—including socio-demographic, household, car use, and attitude factors—influence these preferences. Finally, we provide policy recommendations, including targeted education and communication, income-based incentives, accessible charging infrastructure, and a regulatory framework supportive to technology development and user protections.