Riot Games

Principal Machine Learning Engineer (Personalization, Matchmaking, & Player Experience AI) - Publishing Platform

Los Angeles, USA; Mercer Island, USA · Principal

Sponsorship not specifiedDetected 76 days ago

RedisKafkaMachine LearningTensorFlowPyTorchData EngineeringA/B TestingExperimental DesignCommunication

About the role

Your work shapes how players connect, discover communities, and experience matchmaking that feels meaningful and equitable.
We will look at your past studies and experience, but for this role, we also look for dedicated people with a personal relationship with games.

Define and lead the modeling architecture for personalization, matchmaking, social graph recommendations, and player/community discovery.
Develop models for skill inference, player behavior prediction, trust & safety signals, and multi-objective optimization across fairness, latency, and experience quality.
Build and optimize real-time inference systems for personalized content, store offers, matchmaking, and player interactions at global scale.
Partner with Data Engineering and Product to shape data schemas, feature pipelines, telemetry standards, and model observability across the ML lifecycle.
Define Responsible AI standards and implement fairness audits, bias mitigation, transparency, and safety mechanisms for matchmaking and social systems.
Mentor senior ML engineers and data scientists, influencing system design, experimentation strategy, and modeling craft across organizations.
Represent the ML discipline in cross-functional design reviews, driving alignment on technical decisions, data contracts, and long-term strategy
You'll partner closely with Product, Data Engineering, and Software Engineering to transform large-scale social graph, matchmaking, and behavioral data into adaptive, fair, and player-centric AI systems.
That mission drives every decision in our quest to create games and experiences that make it better to be a player.
Our goal is to create collaborative teams where you are empowered to bring your unique perspective everyday.

10+ years in ML/Applied AI
3+ years in principal/staff-level technical leadership.
Experience with large-scale, real-time ML systems (recommendations, personalization, matchmaking).
Proficiency in PyTorch, TensorFlow, JAX, and modern data/serving tools (Ray, Kafka, Flink, Redis).
Track record of setting ML strategy and standards across teams.
Familiarity with Vertex AI, SageMaker, or internal large-scale inference systems.
Experience integrating ML systems with live-service game backends.
For this role, you'll find success through craft expertise and a collaborative spirit that prioritizes the delight of players.
Professional background in gaming, player modeling, or social ecosystems.
Experience with trust & safety, toxicity detection, or community health models.

Riot focuses on work/life balance, shown by our open paid time off policy and other perks such as flexible work schedules.
We offer medical, dental, and life insurance, parental leave for you, your spouse/domestic partner, and children, and a 401k with company match.
Check out our benefits pages for more information.
Drive adoption of advanced modeling approaches including contextual bandits, reinforcement learning, graph ML, and session-aware personalization.

At Riot Games, we put players first.
Whether you're working directly on a new player-facing experience or you're supporting the company as a whole, everyone at Riot is part of our mission.
If that sounds like the kind of place you want to work, we're looking forward to your application.

This listing is sourced directly from Riot Games's careers page and normalized into a canonical job model.