The ever-growing obesity pandemic is rapidly evolving into the greatest health challenge of our generation. For the first time, the number of individuals with obesity have now surpassed those living with malnutrition. Our failures, which have occurred regardless of the development of novel anti-obesity medications and increasing global access to metabolic surgery, emphasize the need for a better understanding of the complex mechanisms underpinning obesity within our current therapeutic paradigms. In this review, we discuss the sleeve gastrectomy—currently the most commonly performed metabolic surgery worldwide—through the lens of the gut microbiome’s diverse influence on obesity-mediated enteroendocrine, immunologic, and metabolic pathways. By providing bariatric surgeons a clinical primer with which to understand and critically appraise gut microbiome research, we hope to dispel the notion that a perfect sleeve is merely a technical achievement. Instead, a perfect sleeve is one that should be tailored to an individual’s metabolome while harnessing the properties of the gut microbiome to help predict and optimize metabolic outcomes.