Jack Diamond is a partner at the firm of Mahoney Diamond & Harnais. He is an experienced Massachusetts criminal defense lawyer concentrating in the representation of persons charged with the crime of drunk driving ( OUI DUI DWI ). Jack Diamond is widely recognized as one of the best OUI (DUI, DWI Drunk Driving) lawyers in the Commonwealth of Massachusetts.

Jack Diamond has been successfully representing persons charged with drunk driving, OUI, DUI and DWI, in Boston and throughout Massachusetts for over 14 years. He is an experienced and accomplished attorney, dealing with matters including, intoxication, motor vehicle operation, accidents, citations, impairment, license suspensions, blood tests, breath tests, blood alcohol content, roadblocks, sobriety checkpoints and field sobriety tests. To better serve his clients, Jack Diamond is involved with several local and national criminal defense and drunk driving (OUI DUI DWI ) defense organizations including, National College for DUI Defense, National Association of Criminal Defense Lawyers and Massachusetts Association of Criminal Defense Lawyers.

Current Employment Positions:

Trial Lawyer

Areas Of Practice:

  • Criminal Defense
  • Drunk Driving Defense
  • Drug Offenses
  • Firearm Offenses

Litigation Percentage:

  • 100% of Practice Devoted to Criminal Defense Litigation (95% OUI Defense)

Bar Admissions:

  • Massachusetts, 1990
  • U.S. District Court District of Massachusetts, 1992


  • New England School of Law, Boston, MA, 1990
    J.D., Doctor of Jurisprudence
  • Boston College, Chestnut Hill, Massachusetts, 1983
    B.S., Bachelor of Science

Professional Associations and Memberships:

  • National College for DUI Defense (NCDD) Member
  • Association of Trial Lawyers of America (ATLA) Member
  • Massachusetts Academy of Trial Attorneys (MATA) Member
  • Massachusetts Association of Criminal Defense Lawyers (MACDL) Member
  • National Association of Criminal Defense Lawyers (NACDL) Member
  • Massachusetts Bar Association (MBA) Member
  • Boston Bar Association (BBA) Member
  • Norfolk County Bar Association Member
  • Quincy Bar Association Member

Past Employment Positions:

  • Suffolk County District Attorney's Office, Assistant District Attorney, 1990 - 1994
  • Boston Municipal Court, Head Administrative Assistant, 1987 - 1990

Birth Information:

1961, Boston, Massachusetts, United States of America