Riot Games is seeking a Senior Principal Machine Learning Engineer to lead the modeling architecture that powers player personalization, matchmaking, and social experiences within the Central Product Insights group. In this on-site role based in Los Angeles, you will partner with Product Leaders, Software Engineers, and Data Engineers to design and deploy real-time, scalable ML systems that support the social graph, presence, chat, and matchmaking telemetry. You will define and drive the modeling architecture for the player intelligence graph, develop churn and revival models, and drive multi-objective frameworks that balance fairness, latency, and user experience. You will establish evaluation protocols and enable governance for data, models, and observability. You will build real-time inference systems for personalized content, store offers, matchmaking, and player interactions; integrate low-latency data pipelines and feature stores; and advance contextual bandits, reinforcement learning, and graph ML for adaptive, session-aware personalization. You will collaborate with Product, Data Engineers, and Game Engineers to define data schemas, feature lineage, and model observability, and you will drive automation and reliability across the data-to-ML lifecycle. You will mentor senior ML engineers and data scientists and contribute to hiring and ML excellence. Required qualifications include 15+ years in machine learning or applied AI, 3+ years in principal or staff-level leadership, deep expertise in graph ML, reinforcement learning, and representation learning, and proficien

Riot Games is seeking a Senior Principal Machine Learning Engineer to lead the modeling architecture that powers player personalization, matchmaking, and social experiences within the Central Product Insights group. In this on-site role based in Los Angeles, you will partner with Product Leaders, Software Engineers, and Data Engineers to design and deploy real-time, scalable ML systems that support the social graph, presence, chat, and matchmaking telemetry. You will define and drive the modeling architecture for the player intelligence graph, develop churn and revival models, and drive multi-objective frameworks that balance fairness, latency, and user experience. You will establish evaluation protocols and enable governance for data, models, and observability. You will build real-time inference systems for personalized content, store offers, matchmaking, and player interactions; integrate low-latency data pipelines and feature stores; and advance contextual bandits, reinforcement learning, and graph ML for adaptive, session-aware personalization. You will collaborate with Product, Data Engineers, and Game Engineers to define data schemas, feature lineage, and model observability, and you will drive automation and reliability across the data-to-ML lifecycle. You will mentor senior ML engineers and data scientists and contribute to hiring and ML excellence. Required qualifications include 15+ years in machine learning or applied AI, 3+ years in principal or staff-level leadership, deep expertise in graph ML, reinforcement learning, and representation learning, and proficien