Senior Staff/Technical Lead Machine Learning Engineer

About the Role

Harnham is seeking a Senior Staff/Technical Lead Machine Learning Engineer to join a fast-growing, mission-driven tech company in the behavioral modeling and personalization space. In this role, you will lead a team and be central to building and scaling ML-powered products, particularly in ad optimization and recommendation systems. The company leverages one of the largest consented behavioral datasets in the US to deliver private-by-design AI solutions for top global brands.

Responsibilities

• Design, build, and deploy end-to-end machine learning models focused on ad optimization and recommendation systems.
• Develop ML pipelines and production systems that leverage rich behavioral signals to drive user value and business ROI.
• Partner with product and R&D teams to ideate and execute on high-impact, ML-first product strategies.
• Lead experimentation and model evaluation in a fast-paced, data-rich environment.
• Contribute to the development of scalable infrastructure using tools like Airflow, Spark, and CI/CD platforms.
• Work cross-functionally to bring zero-to-one ML products to the market and continuously refine them post-launch.
• Stay updated on emerging ML techniques in recommendation systems, behavioral modeling, and model optimization.

About the Candidate

Expectations:

• MSc or PhD in a STEM field.
• Proven experience building and deploying machine learning systems in a commercial setting.
• Strong background in AdTech or recommender systems with an understanding of personalization and targeting.

Nice to Have Skills:

• Hands-on experience with orchestration tools (Airflow, Bazel) and data infrastructure (Spark, SQL, Scala, Python).
• DevOps knowledge including CI/CD best practices and production model monitoring.
• Familiarity with cloud platforms (AWS, Databricks) and ML tooling (MLFlow, TensorFlow, Kubernetes).
• Strong collaboration and communication skills with a product-oriented mindset.
• A bias toward action and a