Senior Lead Machine Learning Engineer, Agentic AI at Upwork

This role is designed for a seasoned engineering leader with 8–12+ years of experience who has transitioned into the cutting edge of "Agentic AI." The ideal candidate bridges the gap between applied research and production-grade platform engineering. You should have a deep track record of building LLM-powered products, specifically focusing on multi-agent systems, tool-calling, and autonomous workflows that operate reliably at scale. This is a high-impact opportunity to help launch and shape a new international operational hub in Lisbon, Portugal. While the role begins through a local partner during the hub's establishment (expected through 2026), you will be a core part of the team building the foundational infrastructure for agentic intelligence. You'll enjoy the stability of a Nasdaq-listed company with the "greenfield" energy of building a new engineering center from the ground up. **You might be a good fit if you...** * Have 4+ years of experience specifically building and shipping LLM-powered products in production. * Are an expert in Python and distributed systems, capable of designing low-latency inference and orchestration services. * Know how to close the loop between evaluation harnesses, LLM fine-tuning (SFT/RLHF), and runtime policy. * Want to lead technical strategy for multi-agent frameworks, including protocols like Model Context Protocol (MCP).