Gregory was born and raised in Los Angeles, California. He received his B.S in Business Administration for Accounting at the California State University, Northridge, in 1978.  He was a member of the Beta Alpha Psi the national accounting fraternity.  

He passed the CPA exam on his first taking of the exam and was licensed to practice as a CPA in California in 1980 . He is currently a member of the American Insttiue of Certified Public Accountants and The California Society of CPAs.

Gregory is the president of Simon Accounting Group, formerly named Belinkoff and Simon, with over 40 years of accounting, tax and consulting experience. Prior to joining the Simon Accounting Group, Gregory spent several years with an international and large regional accounting firms.  Gregory practice areas include accounting, tax and business consulting and planning for emerging and closely held businesses and high net worth individuals including several types of health care professionals.