ABSTRACT Yeasts have been intimately connected with human civilization for millennia, originally used for fermentation in food and beverage production. This article explores the multifaceted roles of yeasts—particularly Saccharomyces cerevisiae —as both a model organism and a cell factory. The historical journey of yeast research is chronicled from early fermentation practices to its central role in the molecular biology revolution. Notable discoveries using yeast have led to numerous Nobel Prizes, demonstrating its power in elucidating fundamental biological processes such as the eukaryal cell cycle, protein trafficking, transcription, and autophagy. The deep conservation of cellular pathways between yeast and humans, such as AMPK/Snf1 and TORC1/Tor1 signaling, further underscores yeast's value in biomedical research. Beyond its use in basic science, S. cerevisiae has become a preferred host for industrial biotechnology due to its genetic tractability, safety status, and ability to scale fermentation processes. Yeast has been engineered to produce a broad range of chemicals, fuels, and pharmaceuticals. Advanced tools in metabolic engineering—including genome‐scale metabolic models, multi‐omics analyses, and adaptive laboratory evolution—have driven remarkable improvements in yield, productivity, and strain robustness. These tools also offer insights into fundamental metabolic regulation and cellular adaptation. As the article discusses, yeast has not only illuminated the molecular workings of eukaryal life but also transformed industrial biotechnology. Its legacy and continued evolution affirm its indispensable role in science and technology.