This is not a maintenance role. This is a reinvention role. Leidos is seeking a Principal Software Engineer to provide technical leadership for the design and delivery of AI-enabled software platforms and developer tools that support modernization of mission-critical systems. This Principal Software Engineer role is responsible for system-level technical leadership and defines architectural direction within their domain, resolves complex cross-cutting technical challenges, and shapes how teams design, build, and operate software. The Principal Engineer is a hands-on technical leader who influences outcomes through technical excellence, architectural clarity, and mentorship, not through formal management authority. This is a role for builders who bias toward action, who believe disruption can coexist with rigor, and who want to apply cutting-edge AI to the problems that matter most. Mission Context Our teams modernize software systems that support critical national missions across regulated and safety-critical domains. These systems require: High reliability, security, and resilience Scalable and maintainable architectures Responsible, governed use of AI technologies As a Principal Software Engineer, you will shape the technical foundations that enable these systems to evolve safely and efficiently over time. Why Join Us? Shape the technical foundations of mission-critical systems Lead real production engineering—not slideware architecture Apply AI responsibly to complex, high-stakes problems Operate at the highest technical level without moving into management
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Job Type
Full-time
Career Level
Mid Level
Number of Employees
11-50 employees