Court Admissions
- Superior Court, District of Columbia, 1968
- U.S. Court of Appeals for the District of Columbia, 1968
- U.S. Supreme Court, 1972
- Maryland Court of Appeals, 1974
- U.S. District Court, Maryland, 1975
- U.S. Tax Court, 1986
Education
- Grinnell College, 1960–1962
- George Washington University, A.B 1964
- George Washington University School of Law, LLB 1967
- U.S. Navy JAG School, 1968
- Continuing professional education – throughout
Professional Affiliations
- American, Maryland, Montgomery County and District of Columbia Bar Associations
- Estate Planning Council of Suburban Maryland (Chair, 1990–1991)
- The Executive Committee (TEC)(1993–1996)
Career
- George Washington University Law Review (Managing Editor 1966–1967)
- Hollabaugh & Jacobs (Clerk, 1966–1967)
- U.S. Navy JAG (1968–1970)
- Antitrust Division, U.S. Department of Justice (1970)
- Arent, Fox, Kintner, Plotkin & Kahn (1970–1974)
- Hadley & House/Hadley, House & Rabin (1974–1997)
- Donald H. Hadley. LLC (1998–present)
Service Positions
- Rockville Planning Commission (Commissioner 2010–present, Chair 2014, 2015)
- Rainbow Place Shelter for Homeless Women (Counsel, 2015–present)
- The Wesley Seminary: Foundation Board (1998–2010, Chair 2009–2010), Board of Governors (2009–2010)
- Multiple: youth organizations (scouts, athletics), church service positions; community associations