Fundamental geobiological transitions in Earth’s history—like the evolution of oxygenic photosynthesis and rise of oxygen—present big and complex problems that demand a blend of insights from comparative biology, biochemistry, ecology, geology, geochemistry, and paleontology. Each of these perspectives has strengths and weaknesses. For example, comparative biology lends a high level of mechanistic detail and enables rigorous hypothesis testing but can only help ordinate evolutionary events in relative time, and because it relies on extant organisms, is blind to extinction. Geology and geochemistry on the other hand can provide an empirical historical record of geobiological processes but have challenges associated with accurately reading paleoenvironmental chemistry from sedimentary rocks and can only paint metabolic and ecological processes in broad and coarse brushstrokes. But because geological and biological records present different views of the same history, there is substantial opportunity in combining understanding gained from these different perspectives. We leverage these different ways of knowing to tackle a range of historical geobiological problems.