Law Offices of William M. Nassar & Associates Inc

For estate planning services or legal counsel
for your business needs, call 866-204-7554

For estate planning services or legal counsel for your business needs, call:

Integrity. Commitment. Excellence.


Ernest H. Mattison

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Practice Areas

  • Estate Planning
  • Probate
  • Trust Litigation
  • Guardianships
  • Conservatorships
  • Business

Bar Admissions

  • Arizona
  • California


  • Special Act and Performance Achievement, IRS


Ernie Mattison has worked in the private sector from 2000 to present, with Ernest H. Mattison, Jr., CPA & Associates, a local firm specializing primarily in Federal and California tax defense for individuals, corporations and employment tax issues. He has secured major tax reductions and tax removal through audits, IRS appeals, Offer in Compromise, Fraud Penalty removal, related Penalty Abatements and Tax Court petitions with subsequent successful settlement negotiations.

Previous to private practice, he spent the decade of the 90s as a Field Tax Auditor with the Internal Revenue Service at that agency’s Riverside and then San Bernardino, CA offices. While with the IRS, his audit inventory included all sizes of Sch Cs, small and large corporations, partnerships, employment tax audits and development of fraud cases. He received numerous awards from the IRS, including Special Act and Performance Achievement.

He was the Chief Financial Officer of the local IRS Union Chapter for 14 years (1999-2013).

Mr. Mattison passed the multi-part CPA exam in 1992 leading to his licensure in both Arizona and California and received his Enrolled Agent License following separation from the IRS in 2000.

Prior to his affiliation with the IRS, between 1970 and 1987, Mr. Mattison’s career was in Workers’ Compensation where he was a Claims Administrator with California State Compensation Insurance Fund; a Claims Investigator and Hearing Officer with the Ohio Bureau of Workers’ Compensation; a Hearing Representative for Gates McDonald & Co for Northwest Ohio; and finally, chief negotiator for settlement with the two largest Northwest Ohio plaintiff work comp law firms.

Mr. Mattison founded Ernest H. Mattison, Jr, CPA & Associates in 2000.

He has been associated with William M. Nassar, Esq. since 2017.


  • University of Toledo, Toledo, Ohio
    • Master of Science - 1980
    • Major: Accounting
  • University of California, Riverside
    • B.A., Bachelor of Arts - 1970

Past Positions

  • Internal Revenue Service, Field Tax Auditor
  • IRS Union Chapter, Chief Financial Officer, 1999 to 2013
  • California State Compensation Insurance Fund, Claims Administrator
  • Ohio Bureau of Workers’ Compensation, Claims Investigator
  • Ohio Bureau of Workers’ Compensation, Hearing Officer
  • Gates McDonald & Co for Northwest Ohio, Hearing Representative
  • Ernest H. Mattison, Jr, CPA & Associates, Founder, 2000 to 2000