Principal Applied Scientist

Microsoft
U.S. / San Francisco Bay area / New York City metropolitan area2026-04-08onsite

About the job

As a Principal Applied Scientist on our team, you will design and implement large-scale machine learning models, driving their deployment into production and translating your expertise into tangible revenue impact. This role offers a unique opportunity to enhance your skills in building and deploying machine learning models at scale. You will gain invaluable experience analyzing model behavior within a complex, multi-layered model stack, and understanding the intricate interactions between various algorithms. Additionally, you will stay at the forefront of state-of-the-art approaches in this domain.

Responsibilities

Build large scale machine learning models for text and numerical data, deploy models in production.

Run A/B testing, analyze impact of model metrics and possible model failure modes on business KPIs.

Conduct data exploration and analysis of new features and model improvements.

Establish scalable pipelines for data processing and analytics, model training and validation.

Establish automated processes to monitor system health using agentic workflows.

Track relevant state-of-the-art approaches in the field, identify and implement applications to improve the modeling stack.

Mentor less experienced scientists on the team.

Qualifications

Minimum

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.

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

Master's Degree in Statistics, Econometrics, Computer Science, Electrical or Computer Engineering, or related field AND 9+ years related experience (e.g., statistics, predictive analytics, research)

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

OR equivalent experience.

5+ years customer-facing, project-delivery experience, professional services, and/or consulting experience.

Machine Learning Model Expertise: Deep experience designing, training, and optimizing large-scale machine learning models, particularly transformer-based models and large language models, with a strong focus on production deployment and performance.

LLM Inference & Fine-Tuning: Proven ability to build and optimize high-performance LLM inference pipelines and apply advanced fine-tuning techniques (e.g., SFT, LoRA, RLHF) to adapt foundation models for domain-specific use cases.

Model Quality & Evaluation: Strong expertise in developing robust evaluation frameworks for ML and LLM systems, including automated metrics, human evaluation, benchmarking, and monitoring for issues such as hallucination, bias, safety, and model regression.