Human Resources Business Partner

Castelion; Torrance (CA); On-site; USD 90,000 - 130,000; Full time

Job summary

Castelion is seeking a Human Resources Business Partner (HRBP) to serve as a strategic advisor to leaders and employees, guiding organizational effectiveness, talent development, and workforce performance across Castelion.

This role partners with business leaders to align people strategies with objectives, offering guidance on design, performance management, employee relations, leadership development, and workforce planning in a fast-growing environment.

Qualifications

• 5+ years of progressive HR experience, including HRBP work with technical, engineering, or manufacturing teams.
• Experience supporting both exempt and non-exempt populations in a fast-paced environment.
• Strong knowledge of employment law, employee relations, and HR best practices.
• Ability to influence without authority and build credibility across all levels.

Responsibilities

• 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.
• 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.
• 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.
• 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.
• 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.

Skills

HR Business Partner experience

Influence without authority

Analytical skills

Stakeholder management

Fast-paced environment

Education

Master's degree / HR certification

Job description

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, ownership, and excellence are decisive advantages - and we're building a world-class team to turn bold ideas into real capability.

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.

Castelion offers a generous benefits package. Please refer to the bottom of our Careers page for more details.

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.

Additional Eligibility Requirements

This position may require access to classified information or restricted U.S. Government sites, systems, or information, as determined by the Company and/or applicable U.S. Government requirements. If the position is so designated, your employment in the role may be contingent upon your ability to obtain and maintain the required U.S. Government security clearance or other government authorization, and to satisfy any citizenship or other eligibility requirements imposed by applicable law, regulation, executive order, or government contract requirements. You will be notified if and when such requirements apply.

Affirmative Action/EEO Statement

Castelion is an Equal Opportunity Employer. We are committed to providing equal employment opportunities to all applicants and employees without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, age, disability, genetic information, protected veteran status, or any other characteristic protected by applicable federal, state, or local law.

Castelion is committed to providing reasonable accommodations to qualified individuals with disabilities throughout the application and hiring process. If you require a reasonable accommodation to complete an application, participate in the interview process, or otherwise participate in the hiring process, please contact [e-mail]. Requests for accommodation will be considered on an individual basis and handled in accordance with applicable law.

Castelion is committed to fostering a workplace where employment decisions are based on qualifications, business needs, and the ability to perform the essential functions of the role, with or without reasonable accommodation.

EAR/ITAR Requirements

This position requires access to export-controlled information, and as such, employment (or hiring of a contractor) is contingent upon the candidate’s ability to access all applicable export-controlled information without additional export licensing being required by the Bureau of Industry and Security and/or the Directorate of Defense Trade Controls.