Lead Research Scientist, Foundation Models and Agentic Systems - Optum AI

Optum is a global organization that delivers care, aided by technology to help millions of people live healthier lives. The work you do with our team will directly improve health outcomes by connecting people with the care, pharmacy benefits, data and resources they need to feel their best. Here, you will find a culture guided by inclusion, talented peers, comprehensive benefits and career development opportunities. Come make an impact on the communities we serve as you help us advance health optimization on a global scale. Join us to start Caring. Connecting. Growing together.

About Optum and Optum AI

Optum AI is UnitedHealth Group's enterprise AI team. We are AI/ML scientists and engineers with deep expertise in AI/ML engineering for health care. We develop AI/ML solutions for the highest impact opportunities across UnitedHealth Group businesses including UnitedHealthcare, Optum Financial, Optum Health, Optum Insight, and Optum Rx. In addition to transforming the health care journey through responsible AI/ML innovation, our charter also includes developing and supporting an enterprise AI/ML development platform.

Optum AI is building foundation models and agentic systems that can understand complex healthcare data, reason about clinical workflows, and safely assist clinicians and patients at scale. We're looking for a lead research scientist who wants to push the frontier of:

• Pretraining and posttraining of LLMs/SLMs (including RL, RLHF, RLAIF), and
• Agentic systems that plan, use tools, and operate in real healthcare workflows.

This role is ideal for a researcher who enjoys turning openended ideas into stateoftheart models, publishing in top venues, and seeing their work deployed to improve health outcomes for millions of people.

You'll enjoy the flexibility to work remotely * from anywhere within the U.S. as you take on some tough challenges. For all hires in the Minneapolis or Washington, D.C. area, you will be required to work in the office a minimum of four days per week.

Primary Responsibilities:

• Lead research on pretraining and posttraining of language models
  • Design and train domainspecialized LLMs and smaller language models (SLMs) for healthcare applications
  • Explore novel pretraining objectives, architectures, and data curation strategies
  • Develop posttraining pipelines (RL, RLHF, RLAIF) to align models with clinical best practices, safety guidelines, and user preferences
  • Develop RL/RLHF/RLAIF methods at production scale
  • Design reward models and feedback collection strategies with clinicians and domain experts
  • Implement and evaluate RLbased finetuning of foundation models using human and AI feedback
  • Work with platform teams to run largescale, distributed experiments on modern GPU/cloud infrastructure
• Build and study agentic systems for healthcare
  • Design agent architectures that can plan, call tools/APIs, interact with retrieval systems (eg, RAG), and handle multistep clinical workflows
  • Investigate memory, planning, and tooluse strategies to make agents reliable, controllable, and debuggable
  • Define and evaluate benchmarks for agent performance, robustness, and safety in healthcare contexts
• Drive research to production and publish your work
  • Own the endtoend lifecycle of research projects: problem formulation, literature review, experimentation, evaluation, and iteration
  • Collaborate with product teams to translate research into deployed systems that support clinicians, care managers, and patients
  • Publish findings in toptier AI and ML venues (eg, NeurIPS, ICML, ICLR, ACL, EMNLP, KDD, MLHC, CHIL) and present internally to Optum AI and business leaders
  • Ensure safety, fairness, and responsible AI
  • Closely collaborate with the Responsible Use of AI (RUAI) team to embed safety, fairness, and compliance into model and agent design
  • Develop evaluation protocols, diagnostics, and documentation to support model governance and regulatory requirements
• Contribute to highquality engineering and collaboration
  • Build robust training and evaluation pipelines using Python, PyTorch/TensorFlow, and modern ML tooling
  • Follow best practices for software development (tests, packaging, GitHub, code review)
  • Communicate clearly with crossfunctional teams and stakeholders through written documents, technical talks, and presentations

You'll be rewarded and recognized for your performance in an environment that will challenge you and give you clear direction on what it takes to succeed in your role as well as provide development for other roles you may be interested in.

Required Qualifications:

• PhD in Computer Science, Machine Learning, Statistics, Electrical Engineering, or a related quantitative field
• 7+ years of handson experience (including PhD research and post-doctoral research) building and evaluating NLP models using deep learning frameworks (preferably PyTorch) and libraries such as Hugging Face Transformers
• 2+ years of experience with modern NLP / GenAI approaches, such as:
  • LLMs and SLMs (finetuning, evaluation, prompt engineering, safety)
  • Text embeddings, classification, and retrieval-augmented generation (RAG)
  • Distributed or largescale training of generative models
• Demonstrated experience leading research projects (eg, as a primary author on publications, leading subprojects in your research group, or driving technical direction on an industry or internship project)
• Solid research background in machine learning, with emphasis in at least one of:
  • Reinforcement learning / RLHF / RLAIF
  • Natural language processing / large language models
  • Agentic systems, planning, or toolusing agents

Preferred Qualifications:

• Experience building RLHF or RLAIF pipelines endtoend (e.g., reward modeling, feedback collection, policy optimization)
• Experience with agent frameworks (e.g., tooluse, planning, workflow orchestration) or multiagent systems
• Experience working with largescale, realworld data (healthcare, finance, recommendation systems, etc.)
• Experience mentoring junior researchers or engineers
• Familiarity with safe and responsible AI practices, especially in highstakes domains
• Proven solid publication record in toptier AI/ML/NLP venues (e.g., NeurIPS, ICML, ICLR, ACL, EMNLP, KDD, AAAI), ideally including work related to LLMs, RL, or agentic systems Healthcarerelated publications

*All employees working remotely will be required to adhere to UnitedHealth Group's Telecommuter Policy

Pay is based on several factors including but not limited to local labor markets, education, work experience, certifications, etc. In addition to your salary, we offer benefits such as, a comprehensive benefits package, incentive and recognition programs, equity stock purchase and 401k contribution (all benefits are subject to eligibility requirements). No matter where or when you begin a career with us, you'll find a far-reaching choice of benefits and incentives. The salary for this role will range from $110,200 to $188,800 annually based on full-time employment. We comply with all minimum wage laws as applicable.

Application Deadline: This will be posted for a minimum of 2 business days or until a sufficient candidate pool has been collected. Job posting may come down early due to volume of applicants.

At UnitedHealth Group, our mission is to help people live healthier lives and make the health system work better for everyone. We believe everyone-of every race, gender, sexuality, age, location and income-deserves the opportunity to live their healthiest life. Today, however, there are still far too many barriers to good health which are disproportionately experienced by people of color, historically marginalized groups and those with lower incomes. We are committed to mitigating our impact on the environment and enabling and delivering equitable care that addresses health disparities and improves health outcomes - an enterprise priority reflected in our mission.

UnitedHealth Group is an Equal Employment Opportunity employer under applicable law and qualified applicants will receive consideration for employment without regard to race, national origin, religion, age, color, sex, sexual orientation, gender identity, disability, or protected veteran status, or any other characteristic protected by local, state, or federal laws, rules, or regulations.

UnitedHealth Group is a drug - free workplace. Candidates are required to pass a drug test before beginning employment.