Principal Machine Learning Engineer

The opportunity

We are seeking a Principal Machine Learning Engineer to help define and implement the next generation of ML systems for Unity Ads. In this senior role, you will lead the design, development, and deployment of machine learning models that power our ad network, marketplace, and audience targeting tools. You’ll also play a key role in shaping our overall ML strategy, collaborating closely with product, engineering, and research teams.

What you'll be doing

• Architect and deploy scalable, production-grade machine learning systems to optimize ad delivery, bidding strategies, and user engagement.
• Drive the technical direction of ML initiatives—identifying key opportunities, defining roadmaps, and mentoring team members across disciplines.
• Translate state-of-the-art research into practical solutions, ensuring Unity remains at the forefront of ML performance and innovation in the ad tech space.
• Partner cross-functionally with data science, product, and engineering teams to align ML capabilities with strategic business goals.
• Lead experimental design, performance evaluation, and model tuning for high-impact use cases.
• Define requirements for data infrastructure, tooling, and processes to support advanced ML initiatives.
• Promote best practices for model development, testing, deployment, and monitoring.

What we're looking for

• Advanced degree (Ph.D. preferred) in Computer Science, Machine Learning, Statistics, or a related field—or equivalent practical experience.
• Proven track record of delivering impactful ML solutions in production, particularly in large-scale, high-throughput systems (e.g., ad tech, recommendation systems, marketplaces).
• Deep expertise in machine learning frameworks and tools (e.g., PyTorch, TensorFlow, etc.) and a strong understanding of modern model architectures.
• Strong analytical and problem-solving skills, with the ability to formulate and validate complex hypotheses using large datasets.
• Excellent communication skills, capable of articulating technical concepts to both technical and non-technical audiences.
• Experience leading ML initiatives and mentoring other engineers or researchers.
• Familiarity with data pipelines, model ops, and cloud ML deployment

Additional information

• International relocation support is not available for this position.

Life at Unity

As of the third quarter of 2024, more than 70% of the top 1,000 mobile games were made with Unity, and in 2024, Made with Unity applications had an average of 3.7 billion downloads per month. For more information, please visit Unity.

Unity is a proud equal opportunity employer. We are committed to fostering an inclusive, innovative environment and celebrate our employees across age, race, color, ancestry, national origin, religion, disability, sex, gender identity or expression, sexual orientation, or any other protected status in accordance with applicable law. Our differences are strengths that enable us to support the growing and evolving needs of our customers, partners, and collaborators. If there are preparations or accommodations we can make to help ensure you have a comfortable and positive interview experience, please fill out this form to let us know.

Pursuant to the San Francisco Fair Chance Ordinance, we will consider for employment qualified applicants with arrest and conviction records.

This position requires the incumbent to have a sufficient knowledge of English to have professional verbal and written exchanges in this language since the performance of the duties related to this position requires frequent and regular communication with colleagues and partners located worldwide and whose common language is English.

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*Note: Certain locations require a good faith disclosure of the base salary range for the role. The actual salary for the successful candidate may differ based on location, experience, and other job-related factors.