Global food security is increasingly threatened by climate change and population growth, necessitating enhanced agricultural productivity. Photosynthesis, the foundation of life on Earth, represents a crucial target for bioengineering. This chapter explores innovative strategies for enhancing photosynthetic efficiency, focusing on approaches that optimise natural carbon fixation mechanisms, with a particular emphasis on three key research areas: (1) leveraging biophysical carbon-concentrating mechanisms to integrate functional pyrenoids and carboxysomes into higher plant chloroplasts; (2) introducing CAM, Kranz anatomy, and C4 photosynthetic traits into staple crops; and (3) engineering chloroplast genomes. Moreover, the chapter highlights breakthroughs in gene editing, cellular reprogramming, and synthetic biology. Emerging tools, such as spatial-omics and synthetic gene circuits, which are transforming conceptual approaches into commercial applications, are also discussed. This exploration of cutting-edge bioengineering approaches offers promising avenues for developing next-generation crops with improved photosynthetic performance, contributing to a more sustainable and food-secure future.