Join Microsoft Ads as a Principal Applied Scientist and drive innovation in one of the world's largest digital advertising ecosystems. This role focuses on advancing cutting-edge machine learning and AI solutions for ad retrieval, matching, ranking, and generation. You'll leverage state-of-the-art technologies, including LLMs and SLMs, to solve complex, web-scale challenges. Your work will directly enhance user experience and advertiser ROI by optimizing how ads are discovered and presented. We seek a scientist who blends deep research curiosity with a passion for practical execution and shipping impactful products.

Advance research and development in retrieval, ranking, matching, and generative models for advertising. Train, fine-tune, and deploy SLMs, LLMs, and LRMs into production systems. Enhance the Ads ranking platform for improved usability, reliability, scalability, and efficiency. Provide technical leadership, setting project direction and mentoring teams. Stay abreast of AI research trends to ensure solutions remain state-of-the-art. Collaborate effectively with research and engineering teams across the organization.

A Bachelor's Degree in a relevant field (Statistics, Computer Science, Engineering, etc.) with 6+ years of experience, or a Master's Degree with 4+ years, or a Doctorate with 3+ years of related experience is required. Equivalent experience may also be considered. Proficiency in machine learning, deep learning frameworks (PyTorch, TensorFlow, Hugging Face), and large-scale model training is essential. Experience designing and scaling recommendation systems and multi-stage ranking pipelines is highly desirable. Proven ability to ship large-scale ML models to production and influence platform architecture. Track record of publications in top-tier AI conferences is a plus. Must be able to meet security screening requirements, including a Microsoft Cloud Background Check.