This PhD thesis comprises two published papers and four working papers (which are already in the process of publication) on multi-dimensional, interrelated and complex subjects of sustainability and well-being. The thesis covers the history of sustainability and well-being as independent subjects and discusses their evolution into a unified subject matter, sustainability and well-being (SaW). We combined big data methods for discourse analysis with traditional literature review methods to compile an enormous amount of literature to summarise work previously done in this field. Moreover, we analysed 125 years of text data from New Zealand parliamentary debates and policy documents to demonstrate the semantic evolution of SaW in New Zealand. Whilst conceptually sustainability and well-being are interrelated, since well-being is the ultimate goal of all development endeavours and inter-generational sustainability is the constraint, most of the classic economic models have viewed them independently. Prior approaches have led to the development of rather incomplete and to some extent inappropriate policy guiding tools such as GDP. In contrast, contemporary well-being-oriented frameworks in economics have included components of both well-being and sustainability. However, they often take extreme and somewhat differently motivated positions in defining the scope of sustainability and differ significantly in allowing the operating space for development to deliver human well-being. This results in two conflicting notions of sustainability: i) strong sustainability and ii) weak sustainability. In this thesis, we have critically analysed both of these groups and have suggested a balanced and where appropriate nested approach, rather than either of these extreme positions. We have adopted a common measure of inter-generational weak sustainability Genuine Savings (GS) to conduct the empirical case study for long-term sustainability in New Zealand. It transpires that New Zealand is weakly sustainable, however, the increase in total wealth has not always matched population growth resulting in an intermittently occurring savings gap. Furthermore, we have empirically shown the predictive power of GS to predict changes in future subjective well-being in a global context over different time horizons.