Principal Applied Scientist

We are looking for a Principal Applied Scientist to help us deliver breakthrough applied machine learning and information retrieval solutions at enterprise scale. This role is a unique opportunity to apply state-of-the-art techniques—including dense retrieval, hybrid search, multilingual large language models (LLMs), RAG (Retrieval-Augmented Generation), and transformer-based re-ranking models and agentic search—to solve complex challenges in Copilot-driven enterprise search.

As a Principal Applied Scientist, you’ll be responsible for delivering mission-critical innovations that directly improve Copilot experiences such as:

• Agentic Search in modern orchestrator architectures
• Adapting advanced vector search algorithms (e.g., FAISS, ANN, ScaNN) for enterprise-scale semantic retrieval
• Improving classic and neural keyword search quality through deep language understanding
• Designing and training relevance models, including LLM fine-tuning and learning-to-rank (LTR) approaches
• Building robust evaluation pipelines using offline metrics and online A/B experimentation
• Driving cross-org collaboration with platform partners, other applied science teams, and product teams across time zones

This role requires a mix of technical depth, strategic execution, and people management to shape the next generation of AI-powered search experiences.

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.

Responsibilities

• Drive end-to-end applied science projects: From ideation and design to implementation, experimentation, and shipping, you will lead high-impact projects that directly improve Copilot Chat, Copilot Search, and BizChat experiences. This includes identifying search and relevance gaps, formulating innovative hypotheses, and delivering scalable solutions.
• Inspire help to grow a high-performing applied science team: mentor, and empower a team of applied scientists—owning their technical direction, project execution, and career development. You will guide day-to-day work, ensure scientific and engineering rigor, and be accountable for the team’s output and impact.
• Innovate with scientific rigor: Invent and apply cutting-edge techniques in machine learning, natural language processing, and information retrieval to address real-world challenges at enterprise scale. You will design novel approaches for improving retrieval, ranking, query understanding, and semantic search in Copilot systems.
• Document, share, and amplify learnings: Promote a culture of transparency and innovation by capturing experimental results, documenting methodology, and publishing internal learnings. You’ll drive knowledge sharing that enables broader impact across the organization.
• Translate business goals into scientific strategy: Partner closely with product and business stakeholders to align team efforts with high-priority objectives. You will translate ambiguous product requirements into clear, data-driven, and technically feasible directions.
• Collaborate across organizations and time zones: Work cross-functionally with platform engineering teams, peer science orgs, and product managers to ensure alignment, resolve dependencies, and unblock progress. You’ll be a key bridge between applied science innovation and product delivery.

• Embody our Culture and 

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  Microsoft

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