Principal Applied Scientist

Microsoft Ads powers one of the world’s largest digital advertising ecosystems, serving billions of ad recommendations every day. We are seeking a Principal Applied Scientist to shape the scientific direction of our ad retrieval, matching, ranking, and generation systems and translate advances in machine learning and AI into measurable customer and business impact. In this role, you will identify high-impact scientific problems, develop novel machine learning and AI approaches, and lead their translation into reliable production systems. You will advance LLMs, SLMs, LRMs, and other state-of-the-art technologies to solve web-scale challenges. Your work will influence how ads are discovered, matched, ranked, and generated, improving user experience, advertiser ROI, and the efficiency of the Microsoft Ads platform. We are looking for a scientist who combines scientific depth with solid product judgment and execution. You will be expected to set technical direction for ambiguous, high-impact problems; build alignment across science, engineering, and product teams; and guide ideas from research through production deployment and measurable outcomes. You thrive in collaborative, cross-functional environments and raise the technical bar for teams working at web scale. Microsoft’s mission is to empower every person and every organization on the planet to achieve more. As employees, we come together with a growth mindset, innovate to empower others, and collaborate to realize our shared goals. Each day, we build on our values of respect, integrity, and accountability to create a culture of inclusion where everyone can thrive at work and beyond. Starting January 26, 2026, Microsoft AI (MAI) employees who live within a 50-mile commute of a designated Microsoft office in the U.S. or 25-mile  commute of a non-U.S., country-specific location are expected to work from  the office at least four days per week. This expectation is subject to local law and may vary by jurisdiction.

Advance research and development across retrieval, ranking, matching, and generative models. Leverage and improve SLMs/LLMs train, fine-tune, and align models and productionize them. Evolve the Ads ranking platform toward better usability, reliability, scalability, efficiency, and architectural coherence. Provide technical leadership on projects: set direction, coach a distributed team, and influence cross-org strategy. Follow research trends in AI to guide the group keep solutions state-of-the-art. - Collaborate with research and engineering teams.

Required/Minimum Qualifications: Bachelor's Degree in Statistics, Econometrics, Computer Science, Electrical or Computer Engineering, or related field AND 6+ years related experience (e.g., statistics, predictive analytics, research). OR Master's Degree in Statistics, Econometrics, Computer Science, Electrical or Computer Engineering, or related field AND 4+ years related experience (e.g., statistics, predictive analytics, research). OR Doctorate in Statistics, Econometrics, Computer Science, Electrical or Computer Engineering, or related field AND 3+ years related experience (e.g., statistics, predictive analytics, research). OR equivalent experience. Other Requirements: Ability to meet Microsoft, customer and/or government security screening requirements are required for this role. These requirements include but are not limited to the following specialized security screenings: Microsoft Cloud Background Check: This position will be required to pass the Microsoft Cloud background check upon hire/transfer and every two years thereafter.

Master's Degree in Statistics, Econometrics, Computer Science, Electrical or Computer Engineering, or related field AND 6+ years related experience (e.g., statistics, predictive analytics, research). OR Doctorate in Statistics, Econometrics, Computer Science, Electrical or Computer Engineering, or related field