Mannion Prior

Karl Prior

Karl Prior

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(610) 265-7800

Mannion Prior, LLP co-founder and partner Karl Prior focuses his practice on Orphans’ Court and fiduciary litigation including will contests, trust disputes, estate litigation, and fee and commission disputes. Karl has litigated every aspect of Power of Attorney disputes including the capacity of a “principal” to execute a Power of Attorney, abuse of an agent’s authority, revocations of Powers of Attorney, and the existence of an agent under Power of Attorney as a less restrictive alternative to an incapacity proceeding.

Karl has tried numerous matters to jury verdict and bench decision in federal court, the Civil Division of Pennsylvania’s Court of Common Pleas, and in the Orphans’ Court Division of the Court of Common Pleas. Most recently, and over the course of a 15-day trial, Karl successfully defended a triple will contest and domicile dispute. He also has successfully argued in state and federal appellate courts.

Karl has served as a panelist on Orphans’ Court practice and developments at various Pennsylvania Bar Institute seminars and at the Pennsylvania State Trial Court Judges Mid-Annual meeting. Orphans’ Court judges have appointed him as Administrator d.b.n.c.t.a. and as Guardian ad litem, and as such he has pursued claims on behalf of troubled estates and safeguarded the interests of incapacitated persons and minors. He has served as and has lectured on the use of experts in Orphans’ Court matters.


  • B.A. 1986, Temple University

  • J.D. 1989, Georgetown University Law Center

Bar Admissions

  • Admitted to practice in Pennsylvania

  • Admitted to practice in the United States Court of Appeals, Third Circuit

  • Admitted to practice in the United States District Court, Eastern District of Pennsylvania


  • The Best Lawyers in America ©, Litigation and Trusts & Estates – 2018-2019

  • American Lawyer Media and Philadelphia Magazine, Pennsylvania “Super Lawyer” – 2005-2018

  • AV® Preeminent™ Peer Review Rated by Martindale-Hubbell


  • The American College of Trust and Estate Counsel (ACTEC), Fellow

  • Pennsylvania Bar Association

  • Philadelphia Bar Association

  • Philadelphia Bar Association, Probate Section

  • Philadelphia Bar Association, Probate Section Orphans’ Court Litigation and Alternative Dispute Resolution Committee

  • Montgomery Bar Association

  • Montgomery Bar Association Probate Section

  • Montgomery County Orphans’ Court Local Rules Drafting Committee

  • Bucks County Bar Association

  • Bucks County Bar Association Orphans’ Court Section

Previous Experience

  • Cozen O’Connor, 1995-2001

  • Drinker Biddle & Reath, LLP, 1989-1995