<p>Terraforming Mars toward sustainable life-supporting ecosystems poses unprecedented challenges. Extremophilic microbes, which thrive in Earth’s most extreme environments, offer promising biological strategies for initial Mars colonization providing tools for resource mobilization and atmospheric engineering. This review synthesizes experimental evidence on microbial survival Mars-simulated conditions, highlights the ecological roles of extremophilic microbial consortia in biogeochemical cycling. We further discuss cutting-edge synthetic biology approaches to enhance microbial resilience. Yet, we emphasize the need to shift focus from single-species assessments to complex, synergistically interacting microbial communities, which may hold the key to establishing self-sustaining extraterrestrial biospheres. Finally, we consider planetary protection, ethical concerns, and future research priorities to responsibly perform Mars terraforming.</p>