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 aPrincipal Researcherwith 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 aPrincipal 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 this role you will bridge frontier AI researchspanning local Small Language Models (SLMs) NPU-accelerated dense retrieval on-device vector indexes and contextual temporal graphswith 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.

Microsofts 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 thelong-term architectural directionfor Windows Search including indexing pipelines retrieval systems ranking and semantic enrichment.
• Serve as theresearch authorityfor 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 Masters Degree in relevant field AND 7 years related research experience.
  • OR Bachelors 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 architectingend-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 poweragentic workflowsor 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 Masters degree in Computer Science Artificial Intelligence Information Retrieval Systems Engineering or related quantitative discipline.
• Experience: 8 years (Ph.D.) or 10 years (Masters/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 (C17/20) 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.

Required Experience:

IC