Ontology Engineer

Salary: $151000 - 220000 per year Requirements: We require U.S. citizenship and an active TS/SCI security clearance with CI polygraph. We are looking for someone with 12 years of experience plus an advanced degree, or 17 years of experience with a bachelors degree. We need demonstrated experience designing and implementing ontologies, taxonomies, or knowledge graphs in operational or research settings. We require hands-on experience with Semantic Web technologies such as RDF, OWL, and SPARQL. We seek knowledge of ontology engineering methods, data modeling principles, and semantic interoperability frameworks. We need the ability to explain complex technical concepts clearly to both technical and non-technical audiences. Preferred candidates will have experience building and maintaining enterprise knowledge graphs and integrating diverse data sources. Preferred candidates will be familiar with AI/ML workflows and how ontologies improve explainability, reasoning, and decision support. Preferred candidates will have experience leading technical work, mentoring others, and delivering formal knowledge transfer to government personnel or large multidisciplinary teams. Preferred candidates may hold a CDMP or equivalent data architecture certification. Preferred candidates may hold a CKM or comparable knowledge management credential. Preferred candidates may have formal training or certification in Semantic Web technologies, knowledge graphs, ontology engineering, RDF, OWL, or SPARQL. Responsibilities: We will have you design, develop, and maintain domain-specific ontologies, taxonomies, and knowledge graphs in support of Object-Based Intelligence mission objectives. We will have you apply Semantic Web standards and technologies, including RDF, OWL, SHACL, and SPARQL, to model, represent, and query complex data relationships. We will have you build and sustain semantic data integration frameworks that improve interoperability across internal and external object-management systems. We will have you partner with analysts, data scientists, engineers, and government stakeholders to gather requirements and convert mission needs into formal knowledge models. We will have you establish ontology governance processes, standards, documentation, and version-control practices to support consistency and scalability. We will have you support AI/ML initiatives by providing structured knowledge representations that improve explainability, interpretability, and contextual reasoning. We will have you conduct ontology validation, testing, and quality assurance to ensure accuracy, completeness, and alignment with mission needs. We will have you provide technical leadership, mentoring, and knowledge transfer to government personnel and project team members on ontology development and semantic technologies. Technologies: AI Support RDF Security Web More: We are Halcyon Labs, an organization focused on spatial intelligence and mission-driven problem solving, helping decision makers and operators better understand what is happening now and anticipate what comes next. This is a full-time onsite role for an Ontology Lead supporting Object Based Intelligence work, and it requires U.S. citizenship plus an active TS/SCI clearance with CI polygraph. We offer a competitive total rewards package that includes a robust 401(k) with company match, mental health resources, student loan repayment assistance, adoption reimbursement, and pet insurance. The base pay for the Washington, DC metropolitan area is $137,000 to $200,200 annually, with ranges varying by location. We are committed to an inclusive workplace and equal employment opportunity. last updated 28 week of 2026