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About Me

Mario J. DeRossi is a civil litigation attorney practicing in both the federal and state courts of New York.  His practice concentrates in the area of Family Law, including, divorce; child custody; and child support; property division; division of retirement benefits; tax consequences of divorce; annulments; paternity; grandparent's rights; domestic violence; and post-judgment proceedings.

Mr. DeRossi began his career as an officer in the Judge Advocate General’s Corps of the United States Army.  While a Judge Advocate, he served as lead counsel in more than fifty courts-martial.  Most notable, Mr. DeRossi successfully defended fellow officers charged in the highly publicized detainee abuse cases at  Abu Ghraib, Iraq and Bagram, Afganistan.  Mr. DeRossi was also deployed to Iraq as part of Operation Iraqi Freedom, where he served as a military magistrate.


Mr. DeRossi has a unique philosophy in handling Family Law matters.  He believes that every client deserves individual attention and the best representation possible.  Based upon this philosophy, he has developed a successful Family Law practice.  He also recognizes the emotional trauma and pain individuals suffer when going through a divorce.  As a result, he offers his clients the time and the experience necessary to guide them through one of the most difficult experiences in their life.  In every case, Mr. DeRossi, first attempts to bring about a quick, civilized, fair and inexpensive resolution.  However, if that cannot be accomplished, he offers aggressive professional representation.  Mr. DeRossi has developed a reputation for attending to the individual needs of his clients.

Mr. DeRossi is a member of the state bars of New York and Massachusetts.

Mr. DeRossi received his Bachelor of Arts from St. John’s University, graduating magna cum laude.  He received his Juris Doctor from St. John’s University School of Law in 2001.


Practice Areas


  1. Divorce & Separation: 70%
  2. Family: 25%
  3. Commercial: 5%


Payment Types:

Cash, Check, Credit Card

Attorney Endorsements

16 total 

  • No photo

    Mario is an exceptional attorney. His knowledge of family law matters is impressively extensive, but more importantly she has a deep focus on the needs of her clients. Highly recommended!


    Joshua Hecht Litigation Attorney
    Relationship: Fellow lawyer in community

  • Barry J. Gross

    I endorse this lawyer. Mr. DeRossi is an extremely talented and knowledgeable attorney. He is "old school" in that his word is his bond.


    Barry Gross Divorce & Separation Attorney
    Relationship: Opposing Counsel on matter

Contact Info

Stern & DeRossi, LLP

1565 Franklin Avenue
Suite 301
Mineola, NY, 11501


NYCurrently registered 200103/13/2015

Professional Misconduct

We have not found any instances of professional misconduct for this lawyer.
Avvo Contributions
Legal Answers
Award NameGrantorDate Granted
Top 40 Lawyer Under 40The American Society of Legal Advocates2014
Top Ten RankingThe National Academy of Family Law Attorneys2014
2014 New York Metro Rising StarsSuperLawyers2014
Top 40 Under 40The National Trial Lawyers2014
Award for Trial AdvocacyThe Association of the Bar of the City of New York2004
Bronze Star MedalFourth Infantry Division, United States Army2003
Army Commendation MedalTrial Defense Service, United States Army2003
Army Commendation MedalFourth Infantry Division, United States Army2002
Work Experience
TitleCompany NameDuration
PartnerStern & DeRossi, LLP2009 - Present
AssociateStern, Adler & Associates, LLP2006 - 2009
Judge AdvocateUnited States Army2002 - 2006
Association NamePosition NameDuration
The National Academy of Family Law AttorneysMember2014 - Present
The American Society of Legal AdvocatesMe2014 - Present
Nassau County Bar AssociationMember2009 - Present
New York State Bar Association, Family Law SectionMember2009 - Present
Columbian Lawyers AssociationMember2009 - Present
School NameMajorDegreeGraduated
Saint John's University, School of LawLawJuris Doctor2001