The aim of this paper is to investigate sustainable education and positive psychological interventions in schools towards achievement of sustainable happiness and well-being for 21st century pedagogy and curriculum. The growing awareness that sustainability, happiness, and well-being are intertwined takes the discussion of happiness and sustainability to newer levels. Even though scholars and governments are now grappling with questions about policies for sustainability, happiness, and well-being, the general public may not be aware of these connections and none of these topics are well integrated into formal education. Nevertheless, the necessity for transforming education to play a leading role in sustainable education has never been more imperative, and thus it has been taken up extensively in this paper. The concept of sustainable happiness offers an innovative perspective to reinvigorate sustainability education and shape priorities for 21st century learning: contributing to resilient, sustainable happiness and well-being for all. The education sector, however, is conservative and slow to adapt. The author recommends that happiness should be an aim of education, and a good education should contribute significantly towards personal and collective happiness. Broadening this recommendation to consider sustainable happiness and well-being for all is an overarching aim that could assist to reimagine the role of education in the 21st century and serve as the foundation for setting new priorities.