Ariana Zeller

Ariana Flynn Zeller is an attorney at Koller Herlihy LLP.  Her practice covers all aspects of trust and estate law, offering clients a unique blend of experience that spans trusts and estates litigation, comprehensive estate planning, and trust administration. She represents individuals, families, and professional fiduciaries navigating sensitive legal challenges, including will and trust contests, accounting disputes, and breach of fiduciary duty claims.

Ariana’s background in both the planning and administrative sides of the practice provides her with a distinct advantage when disputes arise. Having built foundational estate plans and guided trustees through the administration process, she thoroughly understands the underlying mechanics of estate vehicles. This holistic perspective allows her to effectively manage all aspects of a file, quickly identify administration vulnerabilities, and anticipate opposing strategies in the courtroom. Whether advising clients on proactive risk mitigation or navigating families through highly contentious and challenging dynamics, Ariana focuses on delivering practical, results-oriented solutions.

Ariana has significant experience managing cases through all stages of conflict, from pre-litigation counseling and strategic mediation to contested court proceedings.

Ariana graduated from the University of California College of the Law (formerly, UC Hastings) with a Law and Health Science Concentration. She obtained her undergraduate degree from the University of California, Davis, with a Bachelor of Science in biopsychology. In college, she also played NCAA basketball. While in law school, Ariana earned the CALI Excellence for the Future for the Medical Legal Partnership for Seniors Clinic and participated in the award-winning Health Law Moot Court Team.

Ariana is an active member of several professional organizations. She remains active in the Contra Costa County Bar Association, having served as the President of the Barrister’s Section from 2024-2026. Deeply involved in the local estate planning community, Ariana currently serves as the Secretary of the Tri-Valley Estate Planning Council. Recently, Ariana has been awarded Innovation Tri-Valley Leadership Group’s “20 Under 40” award.