Human Resources Business Partner

Why Castelion, Why Now

Castelion is moving incredibly fast to develop and deliver advanced defense systems at a time when execution matters more than ever. We believe focus and technical excellence are decisive advantages - and we are building a team that can deliver real capability, not just concepts.

This is a rare opportunity to join at an early stage, where your work will directly shape critical systems, influence major technical decisions, and have immediate, real-world impact.

Human Resources Business Partner (HRBP)

The Human Resources Business Partner (HRBP) serves as a strategic advisor to leaders and employees, helping drive organizational effectiveness, talent development, and workforce performance across Castelion. This role partners closely with business leaders to align people strategies with company objectives, providing guidance on organizational design, performance management, employee relations, leadership development, and workforce planning. The ideal candidate thrives in a fast-paced, high-growth environment and is passionate about building scalable people practices that enable exceptional talent to perform at their highest level while supporting Castelion's mission and continued growth.

Responsibilities

Strategic Business Partnership

• Partner with business leaders to improve organizational performance, workforce planning, and team effectiveness, maintaining a 95%+ leadership satisfaction rating through proactive HR support.
• Provide strategic coaching that enables leaders to resolve 90%+ of employee relations and performance matters without escalation.
• Develop and execute people strategies that improve retention, organizational health, and business outcomes, contributing to year-over-year improvements in key talent metrics.

Organizational Effectiveness & Talent Strategy

• Lead workforce planning, talent reviews, and organizational design initiatives that ensure 100% of critical roles have succession or staffing plans.
• Partner with leaders to identify and develop high-potential talent, achieving 90%+ completion of annual talent calibration and development plans.

Performance Management & Employee Relations

• Coach leaders through performance management, investigations, and employee relations matters while maintaining 100% legal and policy compliance.
• Ensure 95%+ of performance improvement plans, corrective actions, and investigations are completed within established timelines and documentation standards.

Leadership Coaching & Development

• Coach managers to improve leadership capability, accountability, communication, and decision-making, resulting in measurable improvements in team performance.
• Partner with leaders to increase manager effectiveness, with 90%+ of leaders demonstrating improvement against leadership development objectives.

Culture & Operational Excellence

• Identify and implement process improvements that reduce administrative effort and improve service delivery, targeting 20%+ annual efficiency gains across HR processes.
• Drive People initiatives that reinforce Castelion's culture of ownership, accountability, urgency, and continuous improvement while maintaining 95%+ completion of key annual People programs.

Basic Qualifications

• 5+ years of progressive HR experience, including HR Business Partner experience supporting technical, engineering, manufacturing, and/or operations organizations.
• Demonstrated experience supporting both exempt and non-exempt employee populations in a fast-paced environment.
• Experience supporting workforce planning, talent development, organizational design, and performance management initiatives.
• Strong understanding of employment law, employee relations, and HR best practices.
• Demonstrated ability to influence without authority and build credibility across all levels of an organization.
• Comfortable operating in a fast-paced, highly ambiguous, high-growth environment.
• Strong analytical skills and ability to translate people data into business recommendations.

Preferred Skills and Experience

• Experience supporting aerospace, defense, manufacturing, hardware, or other highly technical organizations.
• Experience supporting organizations undergoing hypergrowth.
• Master's degree, PHR, SPHR, SHRM-CP, or SHRM-SCP certification.

Other Duties

Please note this job description is not designed to cover or contain a comprehensive listing of activities, duties or responsibilities that are required of the employee for this job. Duties, responsibilities and activities may change at any time with or without notice.

Benefits And Perks

All full-time employees are granted meaningful long-term equity, sharing in the company's significant growth trajectory. We offer four (4) weeks of paid time off, ten (10) company-paid holidays, and comprehensive health benefits - including 100% employee-covered medical and strong dependent coverage, along with dental and vision plans. We also provide paid parental leave to support growing families, a $100 monthly fitness stipend to promote health and performance, and onsite EV charging for convenience. In addition, employees enjoy perks like catered meals, company-covered food during high-demand periods, and a fully stocked kitchen to stay fueled throughout the day.

While this position does not currently require a U.S government-issued security clearance, it may in the near future. Therefore, the ability to obtain and maintain a U.S. government–issued security clearance is required. U.S. citizenship is required, as only U.S. citizens are eligible for a security clearance.

Affirmative Action/EEO Statement

Employment with Castelion is governed on the basis of competence and qualifications and will not be influenced in any manner by race, color, religion, gender, national origin/ethnicity, veteran status, disability status, age, sexual orientation, gender identity, marital status, mental or physical disability or any other legally protected status.