John Siderakis

About John Siderakis

Senior executive with over twenty years of leadership experience spanning education, healthcare and corporate sectors. Recognized for driving operational excellence, leading cross functional teams and delivering transformative results across human resources, labor relations, public safety, compliance, real estate and administrative operations. Adept at navigating complex institutions and multicultural environments, I bring a strategic yet hands on approach to aligning people, processes and financial resources with organizational goals.With leadership roles at the State University of New York (SUNY), including its medical university and teaching hospital, City University of New York (CUNY) and Adelphi University, I have successfully led large teams, modernized operations and fostered high performance cultures during periods of growth and organizational change. My international experience, including overseeing workforce operations for the Olympic Games, further strengthened my expertise in workforce planning, crisis management and regulatory compliance.A former mathematics educator and long time real estate investor, I approach leadership with an entrepreneurial mindset and financial acumen, driving data informed decision making and sustainable outcomes. Whether optimizing HR and labor relations, enhancing operational efficiency or managing multi functional portfolios, I am driven to build resilient systems that empower organizations to thrive.

Experience

1. Chief Human Resources Officer

   The Brearley School

   Dec 2025 — Present · New York, NY, US

   Senior executive responsible for leading human resources strategy, policy and operations for one of the nation’s most respected independent schools. Partner with the COO, Head of School and Heads Council to align workforce strategy with the School’s mission, strengthen organizational culture and ensure that human capital systems, policies and practices support a high performing and inclusive academic community while enabling faculty and staff to thrive in support of Brearley’s commitment to academic excellence, equity and community.Key Areas of Focus & Impact:• Leading the strategic direction of the Human Resources function, overseeing employee relations, talent strategy, benefits administration and organizational development across the community.• Strengthening people systems and operational processes through effective use of human capital technologies to improve service delivery, compliance and data informed decision making.• Advising senior leadership on workforce strategy, organizational effectiveness and change management initiatives that support institutional priorities and long term sustainability.• Ensuring compliance with federal, state and local employment laws while benchmarking policies and practices against peer institutions to maintain best-in-class standards.• Supporting recruitment and retention strategies that attract, develop and retain exceptional educators and staff in alignment with Brearley’s mission.• Advancing a culture of diversity, equity, inclusion and belonging by partnering with leadership to implement initiatives that strengthen equity centered practices across the organization.• Building trust across the community through empathetic leadership, confidential guidance and thoughtful resolution of complex employee relations matters.

Education

• Cornell University

  Human Resources Studies

• Alba Graduate Business School

  Master's degree, MBA

• National & Kapodistrian University of Athens

  Bachelor's degree, Mathematics

Skills

• Training
• Hris
• Personnel Management
• Interviews
• Employee Relations
• Resume Writing
• Recruiting
• Payroll
• Talent Management
• Human Resources
• Employee Engagement