Riot Games is hiring a Principal Machine Learning Engineer to lead the modeling strategy for AI Bots in League of Legends. You will drive the development of agents that understand complex game states and create engaging experiences to improve the new player journey.
What You'll Do
- Lead the modeling strategy for AI Bots on League of Legends, training agents that understand game state, make decisions, and create compelling player experiences across various game modes and skill levels.
- Develop predictive features and signals from gameplay telemetry, unstructured game data, and simulation outputs, ensuring quality, interpretability, and reliability.
- Design and implement ML systems using methods including reinforcement learning and imitation learning, on-/off-policy algorithms, policy gradient methods, behavior shaping, and hybrid systems.
- Define evaluation frameworks for game AI that balance generalizable approaches with genre-specific metrics, adapting methods for the needs of each game mode.
- Ensure the safety, fairness, and trustworthiness of autonomous agents operating in live player environments.
- Collaborate with game and platform engineers, along with UX teams, to integrate models into production.
- Contribute to the AI community at Riot, sharing methods and learnings with other MLEs across the company.
What We're Looking For
- 8+ years of experience delivering ML systems in production, including reinforcement learning, imitation learning, or simulation-based training in rich, interactive environments such as game worlds or multi-agent simulations.
- Proven ability to design modeling strategies and architectures adopted across multiple games or interactive products.
- Expertise working with gameplay telemetry, simulation data, or other complex interactive environments for feature engineering and training.
- Strong track record building and optimizing agent-based systems or world models for dynamic, player-facing environments.
- Hands-on experience with relevant ML methods including reinforcement learning and imitation learning, on-/off-policy algorithms, policy gradient methods, behavior shaping, and hybrid systems.
- Mastery of experiment design, model evaluation, and optimization for autonomous agents.
- Track record of incorporating human considerations into AI applications, such as responsible AI safety and UX best practices.
- League of Legends game context and/or demonstrated ability to learn competitive game systems at a rapid rate.
- Familiarity with integrating ML-driven agents into live game environments with game and platform engineers.
Nice to Have
- Game engineering/C++ experience to write telemetry hooks.
Team & Environment
Reporting directly into the game team, you will collaborate with game engineers, UX designers, and Insights analysts.
Benefits & Compensation
- Open paid time off policy
- Flexible work schedules
- Medical, dental, and life insurance
- Parental leave for you, your spouse/domestic partner, and children
- 401k with company match
It’s our policy to provide equal employment opportunity for all applicants and members of Riot Games, Inc. Riot Games makes reasonable accommodations for handicapped and disabled Rioters and does not unlawfully discriminate on the basis of race, color, religion, sex, sexual orientation, gender identity or expression, national origin, age, handicap, veteran status, marital status, criminal history, or any other category protected by applicable federal and state law.
