Senior Principal AI/ML Engineer in London

Are you motivated by building the shared decisioning foundations for how a live game learns, experiments, and adapts at scale? Join King as a Senior Principal AI/ML Engineer in the Decision Automation team for Candy Crush Saga. In this role, you will help turn fragmented AI/ML and decisioning approaches into scalable, production-grade systems that support faster experimentation, safer adaptation, and more coherent player experiences across the game.

This is a hands-on senior technical leadership role. You will shape direction through architecture, code, prototyping, design reviews, and deep technical judgment. We are not looking for a strategy-only leader. We are looking for someone who can build, simplify, and connect complex systems across team boundaries.

You’ll join the Decision Automation team within Candy Crush Saga: a cross-functional AI/ML team working closely with product, analytics, engineering, game teams, and central platform partners to enable faster, smarter, and more player-centric decisions across the game. Our mission is to accelerate Candy’s learning loop by automating insight generation, experimentation, and adaptation at scale. This role is central to helping define and build the shared architecture needed to make decision automation more scalable, reliable, and reusable across Candy.

The team works across areas such as:

• Causal inference and simulation capabilities usable by product teams
• Generalized automated decisioning systems across multiple game features
• Orchestration across ML systems to reduce conflicting treatments and coordination overhead

With hundreds of millions of players, the systems you help shape will operate at significant scale and influence core player-facing decisions across Candy Crush Saga.

What You’ll Do

• Influence technical direction across Candy Crush Saga in AI/ML and decisioning through credibility, clarity, and delivery
• Stay hands-on through meaningful production coding, technical prototyping, and implementation work on critical paths
• Set a high bar for production AI/ML engineering, including reliability, observability, maintainability, and quality of execution
• Mentor senior engineers and raise the standard of technical judgment, design quality, and cross-team collaboration
• Lead the shared architecture for AI/ML and automated decisioning systems used across multiple components in Candy Crush Saga
• Help unify fragmented approaches into reusable technical foundations that improve consistency, speed, and scalability
• Partner with product and game teams to turn high-value opportunities into reusable capabilities rather than one-off solutions

What You Bring

• Deep AI/ML Expertise
• Deep experience building and shipping production AI/ML systems with meaningful business impact
• Strong applied expertise in areas such as personalization and causal inference
• Track record of connecting AI/ML methodology with real production guardrails, constraints and operational use
• Technical Leadership
• Proven ability to influence technical direction across teams through credibility, clarity, and execution
• Experience defining shared patterns, technical standards, or architectural direction in complex environments
• Ability to lead senior-level technical discussions with substance and precision
• Communication and Collaboration
• Excellent communication skills, with the ability to explain complex technical ideas clearly to both technical and non-technical audiences
• Proven ability to influence across departments and align teams around shared technical direction
• Strong mentoring capability, especially with senior engineers and technical leaders
• Comfortable representing technical work in high-visibility forums, internally and externally
• Product and Cross-Functional Collaboration
• Able to shape product bets through technical insight and co-create reusable capabilities with cross-functional partners
• Effective working across engineering, analytics, product, and platform teams
• Strong judgment in translating business goals into scalable technical systems

Nice to Have

• Experience with large-scale experimentation platforms, personalization systems, or decisioning infrastructure
• Familiarity with game technology, player-facing optimization, or content adaptation systems
• Experience reducing fragmented or bespoke ML workflows into shared technical foundations

Locations: Stockholm, Barcelona and London

About King: With a mission of Making the World Playful, King is a leading interactive entertainment company for the mobile world with more than 20 years of history of delivering some of the world’s most iconic games in the mobile gaming industry, including the world-famous Candy Crush franchise, as well as other mobile titles such as Farm Heroes Saga. King games are played by more than 200 million monthly active users. King, part of Microsoft (NASDAQ: MSFT), has Kingsters in Stockholm, Malmö, London, Barcelona, Berlin, Dublin, San Francisco, New York, Los Angeles and Malta. More information can be found at King.com or by following us on LinkedIn and @lifeatking on Instagram.