Well-being has a major impact on sustained development of economies worldwide; and unionized well-being-improving decisions are key to achieving SDG3, but research on such is rare. This article investigates the determinants of well-being using Life Ladder (LLD), log GDP per capita (LGDP), social support (SSP), and life expectancy at birth (HLE) for panels of 110 countries selected from World Happiness Report 2020, and grouped according to income levels. The empirical panel Granger causality results show that LGDP, SSP and HLE Granger causes LLD in the long-run for low, upper-middle, and high-income countries; but find no evidence of such for the Lower-Middle Income Countries and Global Panel. Evidence from the impulse response and variance decomposition analysis shows that majority of the innovations needed to promote well-being can be found within LLD itself. The policy implication is that though all countries plan to improve well-being, the determinants, innovations, and corresponding reactions vary across countries. K E Y W O R D Simpulse response and variance decomposition analysis, income-based grouping of countries, panel granger causality, sustainable development, unionized well-being-improving decision making, well-being 1 | BACKGROUND Countries around the globe are striving to build economies that are sustainable. This is clearly depicted by the drafting and adoption of the United Nation's Sustainable Development Goals (SDGs; UN, 2020). The 17 integrated SDGs cover a wide spectrum from poverty reduction to decent work and economic growth, industry, innovation, and infrastructure to improve well-being (Diaz-Sarachaga et al., 2018). At the macroeconomic level, sustained increase in average income levels often proxied with growth in gross national income (GNI) per capita are likened to economic development and poverty reduction. Though significant increase in GNI per capita depicts economic growth, sustained improvement that advances and maximizes the well-being of the population is desirable. Thus, improving the well-being of people is key to building long-lasting development of countries globally (Deaton, 2007). The world has made significant improvement in well-being over the past decade. Facts from the World Happinness Report (2020) (WHR2020) puts Finland as the world's most happier country (with happiness score of 7.809 on a 10-point scale) and Afghanistan as the least happiest (happiness score of 2.567). It is worth noting that the variation in happiness rankings have close association with disparities in income. As the world gradually transition to an integrated whole, collaboration, and cooperating among countries can help improve well-being of people worldwide.Based on the undeniable linkage between well-being and income (Zhang & Awaworyi Churchill, 2020), the players in the collaborated network can be selected using income metrics.Facts from the WHR2020 and Helne and Hirvilammi (2015) suggest that when measuring well-being at the country level, most countries pay attention to happiness (proxied wi...