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Sr. Principal Machine Learning Engineer - Central Product Insights

Riot Games

Los Angeles · 3+ years experience · Posted Sep 30, 2026

At a glance

Experience
3+ years experience
Location
Los Angeles

About the role

  • As a Sr. Principal ML Engineer within the Central Product team, you will define and drive the modeling architecture that powers personalization, matchmaking, and social experiences across the player ecosystem.
  • You will lead the AI and modeling layer that transforms foundational data systems into intelligent, adaptive, and fair experiences for players.

Responsibilities

  • Define and lead the modeling architecture that powers player personalization, matchmaking, social graph recommendations, and community discovery.
  • Develop models for churn model, revival models.
  • Drive multi-objective optimization frameworks balancing fairness, latency, diversity, and experience quality.
  • Establish and standardize evaluation protocols (match quality, satisfaction metrics, toxicity mitigation).
  • Build real-time inference systems for personalized content, store offers, matchmaking and player interactions at scale.
  • Partner with the Data Engineers to integrate low-latency data pipelines and feature stores into online model serving.
  • Lead adoption of contextual bandits, reinforcement learning, and graph ML for adaptive, session-aware personalization.
  • Define Responsible AI standards for matchmaking and social systems — including fairness, transparency, and explainability.
  • Drive org-wide model optimization standards - latency, throughput, memory efficiency.
  • Mentor senior ML engineers and data scientists, strengthening system design and experimentation practices.

Requirements

  • 15+ years in Machine Learning or Applied AI; 3+ years in a principal or staff-level technical leadership role.
  • Proven experience in real-time, large-scale ML systems - matchmaking, recommendations, or personalization.
  • Deep expertise in graph ML, reinforcement learning, and representation learning.
  • Proficiency in PyTorch, TensorFlow, JAX, and modern data/serving frameworks (Ray, Kafka, Flink, Redis).
  • Strong understanding of A/B testing, experiment design, and player experience metrics.
  • Track record of defining cross-team ML standards and leading technical direction.

Benefits

  • Open paid time off policy
  • Flexible work schedules
  • Medical insurance
  • Dental insurance
  • Life insurance
  • Parental leave for employee, spouse/domestic partner, and children
  • 401k with company match

Skills

  • PyTorch
  • TensorFlow
  • JAX
  • Ray
  • Kafka
  • Flink
  • Redis
  • Vertex AI
  • SageMaker

Riot Games

Sr. Principal Machine Learning Engineer - Central Product Insights

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