Principal ML Scientist

At Expedia Group, we help travelers explore the world, one journey at a time. As a global travel company powered by passionate people, trusted partnerships, and leading technology, we connect travelers, partners, and advertisers through our consumer brands, B2B network, and travel advertising business. Here, you'll do meaningful work that helps millions of people discover, book, and experience travel with more ease, confidence, and joy. Our five Behaviors-Traveler First, Think Big, Operate with Excellence, Ownership Mindset, and Succeed Together-help foster a supportive environment where people can grow their careers and have the flexibility, benefits, and support to do their best work. Join us and build for travelers everywhere. Principal Machine Learning Scientist, GenAI This role sits within Expedia’s Traveler & Partner Service Platform (TPSP) Product & Technology organization, which builds the core capabilities and experiences that power customer service across the Expedia ecosystem. TPSP enables both travelers and partners to receive high-quality, efficient service through a combination of human support and AI-powered experiences. We are looking for a highly influential science leader to help drive the technical strategy and execution for LLM-powered AI Agent servicing for Expedia travelers and partners, with strong traditional ML based personalization skills along with Agentic AI skillsets within the servicing domain. This role will define and lead the transformation towards scalable, voice and chat based self-service experiences powered by AI agents—reducing customer effort while improving resolution speed, consistency, customer satisfaction, and operational efficiency. As a Principal Machine Learning Scientist, you will partner with key senior leaders to architect the long-term science vision for customer AI servicing, drive complex cross-functional execution, and build a culture of scientific thinking, research and innovation in the organization. You will operate as an indispensable leader, shaping how agentic AI is designed, governed, measured, and scaled across TPSP. What you’ll do • Define and lead the ML strategy for one or more complex product or platform areas (e.g., personalization, search & recommendations, pricing, fraud/risk, or generative AI–powered experiences). • Formulate ill-defined business problems into well-posed ML problems, selecting appropriate modeling approaches and success metrics. • Design and implement state-of-the-art ML models (e.g., deep learning, representation learning, causal inference, bandits, LLM/GenAI where appropriate) and own them through production. • Partner closely with engineering to productionize models, improve data and feature pipelines, and ensure reliability, latency, and scalability requirements are met. • Lead experiment design and evaluation, including A/B tests and offline evaluations; drive decisions with rigorous statistical analysis. • Proactively identify opportunities where ML can unlock new customer and business value, build business cases, and influence product and leadership roadmaps. • Establish and champion best practices for model development, evaluation, monitoring, and responsible AI (fairness, robustness, privacy, and safety). • Provide technical leadership and mentorship to other ML scientists, data scientists, and ML engineers through design reviews, pairing, and informal coaching. • Communicate complex technical topics in clear, concise ways to executives, product leaders, and non-technical stakeholders, influencing direction across teams and organizations. • Collaborate with platform and infra teams to evolve ML tools, feature stores, experimentation platforms, and model monitoring capabilities. Minimum Qualifications • Bachelor’s degree in Computer Science, Statistics, Applied Mathematics, Electrical Engineering, or a related technical field; or equivalent practical experience. • 10+ years of experience in applied ML / data science, including significant experience owning production models in complex domains. • Deep expertise in machine learning algorithms and statistical modeling, such as gradient-boosted trees, deep learning, representation learning, or similar. • Strong Python skills and experience with major ML libraries and frameworks (e.g., PyTorch, TensorFlow, JAX, scikit-learn), and data tools (e.g., Spark, SQL). • Proven track record of shipping production ML systems at scale and driving measurable product or business impact. • Experience designing and interpreting experiments (A/B tests), with solid grounding in statistics (estimation, hypothesis testing, causal inference basics). • Demonstrated ability to lead cross-functional initiatives with product, engineering, and business partners, without formal authority. • Excellent communication skills, with the ability to explain complex ML concepts to diverse audiences and drive alignment. Preferred Qualifications • Advanced degree (MS or PhD) in Computer Science, Machine Learning, Statistics, Operations Research, or a related quantitative field. • Experience in one or more relevant domains, such as: • Personalization, search & recommendations, ranking, or relevance • Marketplace optimization, pricing, or yield management • Fraud/risk modeling, anomaly detection • Natural language processing / LLMs / generative AI • Experience architecting end-to-end ML systems: data/feature pipelines, model training, evaluation, deployment, and monitoring in distributed environments. • Demonstrated impact in technical leadership: setting standards, influencing roadmaps across teams, and mentoring senior ICs. • Familiarity with MLOps practices and platforms (feature stores, CI/CD for models, model monitoring & alerting). • Publications in top-tier ML/AI conferences or journals, or equivalent evidence of thought leadership (talks, patents, open-source). The total cash range for this position in Seattle is $231,000.00 to $323,500.00. Employees in this role have the potential to increase their pay up to $369,500.00, which is the top of the range, based on ongoing, demonstrated, and sustained performance in the role. Starting pay for this role will vary based on multiple factors, including location, available budget, and an individual’s knowledge, skills, and experience. Pay ranges may be modified in the future. Benefits and perks Expedia Group offers benefits and perks designed to support employees and their families, including medical, dental, and vision coverage, paid time off, an Employee Assistance Program, wellness and travel reimbursement, travel discounts, and International Airlines Travel Agent Network (IATAN) membership. Learn more about life at Expedia Group at https://careers.expediggroup.com/life. Accommodation requests Expedia Group is committed to providing an inclusive and accessible recruiting experience. If you need an accommodation or adjustment due to a disability during the application or recruiting process, please submit a request at https://expedia.service-now.com/askeg?id=job_accommodation. About Expedia Group Expedia Group includes three flagship consumer brands - Expedia, Hotels.com, and Vrbo - along with a leading B2B travel business and travel advertising offerings. Across our brands and business, we help travelers explore the world with confidence and ease. Important notice Employment opportunities and job offers at Expedia Group will always come from Expedia Group's Talent Acquisition and hiring teams. Never share sensitive personal information unless you are confident of the recipient. Expedia Group does not extend job offers via email or messaging tools to individuals with whom we have not made prior contact. Our email domain is @expediagroup.com. The official place to find and apply for roles is https://careers.expediagroup.com/jobs/. Equal Opportunity Expedia is committed to creating an inclusive work environment with a diverse workforce. All qualified applicants will receive consideration for employment without regard to race, color, religion, gender, gender identity or expression, sexual orientation, national origin, genetics, disability, age, veteran status, or any other characteristic protected by law. This employer participates in E-Verify. The employer will provide the Social Security Administration (SSA) and, if necessary, the Department of Homeland Security (DHS) with information from each new employee's I-9 to confirm work authorization.