Riot Games

Staff Machine Learning Engineer - League of Legends

Los Angeles, USA · Staff+

Sponsorship not specifiedDetected 5 days ago

Machine LearningStatisticsA/B TestingResearchCommunicationCollaborationMentoring

About the role

Your work could span across personalized player experiences, in-game systems, and matchmaking.
You will also help strengthen craft standards, knowledge sharing, and technical quality across Riot's growing ML engineering discipline.
This role will be located at our Los Angeles headquarters.

Responsibilities

Own end-to-end ML solutions for player-facing problems across personalization, game systems, and matchmaking, from problem framing through production launch and ongoing iteration.
Set technical direction for a League ML domain and create reusable modeling, evaluation, and operating patterns that raise the bar beyond your immediate team.
Build models, recommenders, ranking systems, and decision logic that help players discover the right champions, builds, modes, content, and return paths based on their needs and context.
Develop ML approaches that improve in-game systems and matchmaking quality, balancing player experience, fairness, reliability, and operational constraints.
Partner closely with product managers, designers, analysts, and engineers to shape ambiguous opportunities into clear technical plans and shipped player-facing features.
Design and run experiments to evaluate model quality, player impact, and system tradeoffs.
Operate independently across multiple partner groups, driving multi-month work with limited day-to-day oversight.
Help establish robust monitoring, observability, and support practices for live ML systems as they scale.
You will work across player and product problems through data, modeling, experimentation, launch, and iteration, partnering closely with League product, design, Insights, game engineering, and service engineering teams.
You will report to the Senior Manager, ML Engineering in Tech Foundations while operating as a deeply embedded technical partner to the League team.

Requirements

6+ years of experience delivering ML systems in production, including 3+ years in applied modeling or ML research roles.
Experience in production environments with interacting models, feedback loops, or systems where model behavior has downstream consequences beyond a single prediction.
Comfort with ambiguity - you've shipped in situations where the success metric, the right approach, or both were unclear at the start.
Track record mentoring engineers across roles and levels
Experience with matchmaking, recommendations, multi-objective optimization, or other systems that must balance competing goals.
Experience integrating models into latency-sensitive or high-reliability production environments.
Experience defining telemetry or instrumentation needs in close partnership with software engineers.
Familiarity with responsible AI practices, including fairness, safety, transparency, and operational trustworthiness.
Comfort collaborating across a central craft organization and an embedded product team model.
For this role, you'll find success through craft expertise, a collaborative spirit, and decision-making that prioritizes the delight of players.
Experience building ML systems for games, live service products, consumer personalization, or other player-facing digital products.
Familiarity with causal inference, uplift modeling, contextual bandits, reinforcement learning, or other approaches useful for adaptive player experiences.

Nice to have

Experience bridging research and production - translating papers or prototypes into reliable shipped systems - is a plus.
Familiarity with ML platform components (model serving, feature stores, ML observability) is a plus.

Benefits

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.

Company info

At Riot, we are investing in League of Legends to grow the game for generations to come.
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.

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