Greg Gast and TSC Team

Greg Gast, SPHR  – Founder and President   

  • Organizational Consultant * Leadership Advisor * Human Resources Expert * Entrepreneur
  • Founder and former president of several multi-million dollar professional services firms still operating after 15 years
  • Innovator in organizational consulting, business services and human resources management
  • Faith, family and fitness

Gregory A. Gast, SPHR is a leadership advisor, organizational consultant, entrepreneur and HR expert who is founder and current/former president of several multi-million dollar professional services firms.  Greg founded his current firm Thirdstage Consulting to focus his work on unleashing the power of businesses and non-profits to create value and serve the needs of the community.  He combines his creative problem solving skills with his strategy development talent to provide positive change and sustainable high performance.

Greg’s initial business venture was the founding of Granatt HR, a Human Resources management and consulting firm in 1998, to which he added an employee insurance benefits agency in 2004.  In 2006, Granatt HR partnered with Professional Payroll Solutions to form PROXUS LLC, a full-service payroll and human resources management firm. In 2012 he sold his business interest to his long time partner Jeff Green and became Senior Advisor to the firm.

Greg’s contributions to the field of Human Resources were recognized by his selection as HR Consultant of the Year in the Philadelphia region. Greg previously served on the committee for Professional Learning for the Institute of Management Consultants and the IMC Colorado Board.  His credentials include Senior Professional in Human Resources (SPHR), a Master’s degree in Human Services from John Carroll University, a graduate level certificate in Christian Studies from Fuller Theological Seminary and a Bachelor’s Degree from the College of Wooster.

Thirdstage Consulting Team

The consultants and partners who make up Thirdstage Consulting work together as a team.  Our complementary backgrounds provide a comprehensive range of business, organizational development and human resource expertise.  Client situations are reviewed collectively to access multiple perspectives and explore an array of options.  Greg, as lead advisor is supported by experts in surveys and assessments, compensation, performance management, executive coaching, and training and development.


  • PROXUS – – Full-service Human Resource management and outsourcing firm featuring HR services and payroll administration
  • Brian Gast – – Executive coaching and team alignment