There are conflicting views on the effect of business and entrepreneurial activities on environmental degradation in developing economies. However, none of this study examines whether economic complexity can serve as a policy tool for mitigating the effect of entrepreneurial business activities on a sustainable environment. Economic complexity consists of the structural and economic transformation process from a simple production system to a more complex and innovation‐based one. It predicts the variations in income level and its impact on the choice of goods being produced in an economy. This study examines the moderating effect of economic complexity on the link between entrepreneurship and sustainable environment in Gulf Cooperation Council (GCC) countries from 2006 to 2020. It further examines the validity of the Entrepreneurial Environmental Kuznets Curve (EEKC). The study uses the Driscoll‐Kraay standard error fixed effect, Panels Corrected Standard Errors (PCSE), method of moment quantile regression and Dumitrescu–Hurlin causality that are robust to heteroscedasticity, cross‐sectional dependency and other pitfalls of least square estimating technique. The results validate the inverted U‐shaped EEKC hypothesis across all the quantiles. Economic complexity increases ecological degradation at the lower quantile levels, while it decreases environmental footprint at the upper quantiles. Furthermore, economic complexity moderates the detrimental impact of entrepreneurial activity on the environment at the higher quantiles. A two‐way relationship is established between entrepreneurial activity and the environment, while one one‐way connection from economic complexity to the environment was found. The study recommends that policymakers should encourage innovative rather than necessity entrepreneurs. Entrepreneurs should be encouraged to engage in business activities that are friendly toward preserving the ecological environment, and green innovative activities should be prioritised in their entrepreneurial activities.