Principal Researcher

Join the team that powers one of the most heavily used and most visible capabilities in Windows: Search. As Windows evolves into an agent-first, AI-powered operating system, Search is becoming the primary discovery, reasoning, and grounding layer across user journeys and agentic experiences. The Windows Search and AI Platform team is responsible for building the core Search, indexing, and semantic understanding infrastructure that serves more than a billion users worldwide. 

This role is for a Principal Researcher with deep prior Search experience who will define and drive the architectural direction of Windows Search and related semantic systems, spanning indexing, retrieval, ranking, reliability, and AI-powered experiences. 

As a Principal Researcher on Windows OS Search, you will define the long-term technical vision for Windows Search and semantic retrieval systems and building graph data across systems. You will work across engineering, product, and partner teams to ensure Search is reliable at scale, measurable through quality signals, and extensible for future agentic scenarios. 

We are seeking a visionary and hands-on Principal Researcher to lead the next-generation intelligent search architecture for the Windows Operating System. In this role, you will bridge frontier AI research—spanning local Small Language Models (SLMs), NPU-accelerated dense retrieval, on-device vector indexes, and contextual temporal graphs—with low-level systems engineering. 

You will redefine how over a one billion users discover, access, and interact with files, applications, cloud content, and system state, delivering sub-millisecond lexical and semantic search under strict power, memory, and zero-trust privacy constraints. 

This role blends deep technical expertise in Search systems with cross-org architectural leadership and solid engineering judgment. 

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.

• Research & Architectural Roadmap: Define the multi-year vision for Windows OS search, context-aware indexing, semantic file retrieval, and OS-level neural search systems. 
• On-Device AI & NPU Optimization: Design, adapt, and compress state-of-the-art SLMs and embedding models (via quantization, pruning, and distillation) for local execution on NPUs, GPUs, and CPUs via frameworks like ONNX Runtime/DirectML. 
• Core OS & Storage Integration: Architect low-latency vector indexing structures and hybrid search rankers integrated into the OS file system and runtime, ensuring minimal system memory footprint and battery drainage. 
• Contextual & Semantic Graph Retrieval: Design algorithms that synthesize user activity context, application telemetry, and semantic relationships without compromising user privacy or shipping raw data off-device. 
• Zero-Trust & Local Privacy: Guarantee zero-trust computational isolation where search indexing, embedding generation, and contextual ranking remain strictly on-device. 
• Cross-Disciplinary Leadership: Partner closely with Core OS Systems Engineering, Hardware Acceleration Teams, Silicon Partners (Intel, AMD, Qualcomm), and Product UX teams to ship research innovations into production releases. 
• IP & Scientific Visibility: Drive strategic patent filings, publish in top-tier IR/AI venues, and mentor senior researchers and engineering leads across the division. 
• Define the long-term architectural direction for Windows Search, including indexing pipelines, retrieval systems, ranking, and semantic enrichment. 
• Serve as the research authority for Search-related design reviews, tradeoff discussions, and platform decisions. 
• Drive research clarity across boundaries: Search Platform, Indexer, AI models, telemetry, reliability, and user-facing surfaces. 
• Anticipate future needs for agentic and AI-driven Search, identifying capability gaps and guiding multi-year investments. 
• Partner with Product Managers to translate customer scenarios into durable technical primitives and measurable quality signals. 
• Mentor senior engineers and architects, raising the bar on design rigor, system thinking, and operational excellence. 
• Influence engineering standards, design patterns, and best practices across Search and adjacent platform teams. 

Required/Minimum Qualifications:

• Doctorate in relevant field AND 6+ years related research experience.
  • OR Master's Degree in relevant field AND 7+ years related research experience.
  • OR Bachelor's Degree in relevant field AND 9+ years related research experience.
  • OR equivalent experience.

Additional or preferred qualifications

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. 

Preferred Qualifications:

• 15+ years of experience shipping commercial software or platform technologies at scale. 
• Prior experience owning or architecting end-to-end Search platforms (system, web, enterprise, or OS-level). 
• Experience with semantic search, vector search, knowledge graphs, context-retrieval and content understanding systems. 
• Familiarity with Windows platform internals, diagnostics, and performance tooling. 
• Experience designing Search systems that power agentic workflows or AI-driven user experiences. 
• Solid track record of improving architectural health, reliability, and operational maturity of complex systems. 
• Demonstrated success influencing product and technical direction across multiple organizations. 
• Education: Ph.D. or Master’s degree in Computer Science, Artificial Intelligence, Information Retrieval, Systems Engineering, or related quantitative discipline. 
• Experience: 8+ years (Ph.D.) or 10+ years (Master’s/B.S.) of post-academic research or industry software engineering experience in Information Retrieval, Applied NLP, Machine Learning Systems, or Operating Systems. 
• Track Record: Proven record of either high-impact scientific publications (e.g., SIGIR, KDD, NeurIPS, ACL, EMNLP).
  • OR successful deployment of large-scale search engines, client-side ML pipelines, or OS-level indexing features in commercial operating systems. 

Core Technical Competencies Required 

• Search & Retrieval Systems: Expert knowledge of hybrid search architectures (combining BM25/lexical indices with dense vector embeddings), approximate nearest neighbor (ANN) search algorithms (e.g., HNSW, DiskANN), and re-ranking pipelines. 
• On-Device ML Acceleration: Hands-on experience optimizing and deploying ML models under tight compute, latency, and thermal budgets using ONNX Runtime, DirectML, CoreML, or TensorRT. 
• Systems Programming: Advanced proficiency in C++ (C++17/20) or Rust, with a deep understanding of multi-threading, memory alignment, OS file systems, and concurrency control. 
• Hardware & Silicon Co-Design: Familiarity with NPU architectures, SIMD instruction sets (AVX/NEON), GPU compute kernels, and memory-bandwidth trade-offs on heterogeneous SoC architectures. 
• Privacy-Preserving Computation: Knowledge of federated learning techniques, differential privacy, and local secure enclave execution for contextual intelligence.  

Key Leadership Competencies 

• Strategic Ambiguity Navigation: Capability to convert broad, exploratory research concepts into concrete, executable system architectures. 
• Influence Without Authority: Proven track record of guiding cross-functional teams spanning pure AI researchers, hardware vendors, and core OS engineers toward a unified technical vision. 
• Executive Technical Communication: Outstanding ability to translate deep mathematical and systems trade-offs into compelling business and product cases for senior leadership. 

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This position will be open for a minimum of 5 days, with applications accepted on an ongoing basis until the position is filled.

Microsoft is an equal opportunity employer. All qualified applicants will receive consideration for employment without regard to age, ancestry, citizenship, color, family or medical care leave, gender identity or expression, genetic information, immigration status, marital status, medical condition, national origin, physical or mental disability, political affiliation, protected veteran or military status, race, ethnicity, religion, sex (including pregnancy), sexual orientation, or any other characteristic protected by applicable local laws, regulations and ordinances. If you need assistance with religious accommodations and/or a reasonable accommodation due to a disability during the application process, read more about requesting accommodations.