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About me

I have wanted to be a trial lawyer since I was 6 years old.  At that age, I read a short story called "The Devil and Daniel Webster."  Long story short: after reading it, I knew that being a lawyer could be something heroic, that I could help people who desperately needed help. 


After graduating from law school, I worked as a briefing attorney for United States District Judge Robert W. Porter. 


After completing my term with Judge Porter, I started working at the Austin law firm of Clark, Thomas & Winters.  I handled white collar (RICO) cases, insurance cases, and commercial matters.


My thirst for trials would only be quenched, though, once I started working for the Travis County District Attorney's Office.  I worked in these units: juvenile prosecution, trial court (assigned at various times to the 167th, 299th, and 390th District Courts), grand jury, child abuse prosecution, and the special prosecution (white collar crime) unit.   I was made the first "court chief" of the 390th District Court.


Now I continue representing clients in my criminal defense practice.  I love it.  It allows me to continue helping people, defending the accused both in trial and in negotiations, whichever is more appropriate for my client. 


Languages spoken: Spanish, German

Photos and videos

180009 1253896358

Practice areas


  1. DUI & DWI: 50%
  2. Criminal Defense: 50%


Payment types:

Cash, Check, Credit card

Attorney endorsements

8 total 

Are you an attorney? Endorse this lawyer

  • Rick R Flores

    When I was a prosecutor, I knew I was in for a fight when Bill was the lawyer on the other side. He is extremely sharp and well prepared. His clients are lucky to have him fighting for their rights.


    Rick Flores Criminal defense Attorney
    Relationship: Opposing Counsel on matter

  • Scott Douglas Lewis

    I endorse this lawyer.


    Scott Lewis Social security Attorney
    Relationship: Fellow lawyer in community

Contact info

600 W. 13th Street
Austin, TX, 78701


TXEligible To Practice In Texas 198608/17/2016
We have not found any instances of professional misconduct for this lawyer.
Avvo contributions
Legal answers
Award nameGrantorDate granted
Outstanding Family Justice ProsecutorAustin Children's Advocacy Center1998
Work experience
TitleCompany nameDuration
N/AWilliam B. Mange, P.C.2002 - Present
Assistant District AttorneyTravis County District Attorney's Office1993 - 2002
AssociateClark, Thomas & Winters1988 - 1992
Briefing AttorneyUnited States District Judge Robert W. Porter1986 - 1988
Association namePosition nameDuration
National College of DUI DefenseN/A2004 - Present
Texas Criminal Defense Lawyers AssociationN/A2002 - Present
Austin Criminal Defense Lawyers AssociationN/A2002 - Present
Legal cases
Case nameOutcome
State of Texas v. HRGuilty.
State of Texas v. William BalfourWon - guilty (I represented the State) - 38 TDC
State of Texas v. AHWON --Not guilty
See all legal cases 
Publication nameTitleDate
Texas International Law JournalAntidumping -- Application of Preceding Quarter's Foreign Exchange Rate to Fair Value Determination1985
School nameMajorDegreeGraduated
University of Texas School of LawLawJD - Juris Doctor1986
University of Texas System, AustinPlan II Liberal Arts Honors ProgramBachelor of Arts with High Honors and Departmental Honors1982
Speaking engagements
Conference nameTitleDate
DWI Trial: Defending and Winning a Breath Test CaseDWI Trial: Defending and Winning a Breath Test Case2008
Prosecutor's Skills CourseConfessions2001
New Detectives ClassWarrantless Arrests2000
Prosecutor's Skills CourseFaculty Advisor for Trial Skills Group1999