Mark Edward Swirbalus

Mark Swirbalus


Mark Swirbalus is a private wealth services litigator, trial attorney and advisor in Holland & Knight's Boston office. Mr. Swirbalus focuses his practice on high-stakes trust and estate (T&E) disputes and probate and fiduciary litigation in Massachusetts and other jurisdictions across the country.

Mr. Swirbalus represents individuals, families, charitable organizations and financial institutions as beneficiaries, trustees, executors, administrators and personal representatives. He acts as lead counsel on a broad range of T&E-related disputes, including:

  • trust and will contests involving allegations of undue influence, incompetency and fraud
  • interference with inheritance actions
  • breach of fiduciary duty and removal actions
  • contested accountings
  • trust reformation, modification and interpretation actions
  • irrevocable life insurance trust (ILIT) matters
  • trust and estate property disputes
  • family limited partnership (FLP) disputes
  • trust-held limited liability company (LLC) disputes
  • reasonable deviation and cy pres matters

Mr. Swirbalus is among a small group of lawyers based in the Boston area who dedicate their practice entirely to handling T&E-related disputes, which can be a highly specific and nuanced area of the law. He appreciates the trust that clients place in him and is sensitive to the personal nature of their legal matters. This area of litigation at times can be stressful and disruptive, but he works diligently to enable his clients to continue their daily lives. Mr. Swirbalus finds this work deeply gratifying and gains satisfaction in serving as a sounding board on a wide range of issues for individuals and the future generations of their families.

Clients often look to Mr. Swirbalus not only to guide them to successful resolution of their "once-in-a-lifetime" legal matters through settlement or trial, but also to help them avoid litigation altogether.

Chambers High Net Worth resources comment that Mr. Swirbalus is "considered as Boston's preeminent probate litigator. . . . (he is) one of the leading people in the city at what he does . . . an excellent technician . . . (and) he's got a big world view, he's not swayed by small details. He's a grown-up in this world – he doesn't have to be nasty to represent his client zealously." In addition, other resources add that Mr. Swirbalus "has a good mind for strategy, he's creative and a good writer. . . . (is) the first person I call when I have probate going to litigation."

Mr. Swirbalus also has received praise from Chambers USA resources: he is "top notch," "smart, and has an excellent knowledge of trust matters. He had a plan from day one to address our concerns. . . . tremendous respect for his practice. He is very strategic, smart and … very sensitive and understanding of family dynamics. . . . (he also) is able to step out and earn clients' trust and respect and take the emotion out of probate litigation."

Mr. Swirbalus is a frequent lecturer, and has been asked to speak at conferences and seminars for the following organizations: American College of Trust and Estate Counsel (ACTEC); American Law Institute (ALI); New England Fellows Institute; Massachusetts Bar Association; Boston Bar Association; Massachusetts Continuing Legal Education (MCLE) Inc.; Boston Probate and Estate Planning Forum; Cambridge Forums, Forum on Private Wealth Litigation; Greater Boston Fiduciary Law American Inn of Court; Boston Estate Planning Council and Boston College Law School.

Prior to joining Holland & Knight, Mr. Swirbalus was an attorney at a national law firm, where he co-chaired its litigation department for nearly a decade.

Representative Experience

  • Represented a beneficiary in multijurisdictional litigation to enforce the beneficiary's rights in family trusts that own interests in a number of international companies and high-profile franchises; successfully achieved a negotiated resolution
  • Represented trustees in a removal action based on alleged breaches of fiduciary duty and self-dealing in connection with the creation of a conservation easement and transfers of thousands of acres of Wyoming land among multiple family trusts; prevailed at trial and awarded legal fees and costs; judgment affirmed on appeal
  • Represented a charity in an action relating to diversion of the founder's assets and end-of-life changes to the founder's estate plan, asserting claims for lack of testamentary capacity, undue influence and interference with expectancy; successfully achieved a negotiated resolution
  • Represented a widow in defense of a death-bed conveyance by which her late husband deeded ownership of an historic horse farm to her; prevailed at trial; judgment affirmed on appeal
  • Represented a prominent social services charity in an action to enforce the charity's rights with respect to free healthcare under a century-old charitable bequest; successfully achieved a negotiated resolution
  • Represented trustees in action to enforce the no-contest or in terrorem clause of a trust embroiled in litigation; prevailed on summary judgment, which was affirmed on appeal
  • Represented a family-member executor accused of unduly influencing the family's matriarch to gain control of her estate and the family business; prevailed on summary judgment and awarded legal fees and costs
  • Represented a beneficiary in asserting claims against a trustee for diversion of cross-border assets and self-dealing, and to enforce a subsequent settlement agreement; claims involved issues of U.S. law and Indian law; prevailed on summary judgment, which was affirmed on appeal with an award of legal fees and costs


  • Boston College Law School, J.D.
  • Dartmouth College, B.A.
Bar Admissions/Licenses
  • Massachusetts
  • New Hampshire
Court Admissions
  • All Federal Courts in Massachusetts
  • All Federal Courts in New Hampshire
  • All State Courts in Massachusetts
  • All State Courts in New Hampshire
  • American College of Trust and Estate Counsel (ACTEC), Fellow, Fiduciary Litigation Committee, 2012-Present
  • Cambridge Forums, Forum on Private Wealth Litigation, 2021-Present; Steering Committee, 2023-Present
  • Boston Bar Association, Trusts & Estates Section, Public Policy Committee, 2012-2013; Trusts & Estates Section, Fiduciary Litigation Committee, Co-Chair, 2010-2012
  • Boston Probate and Estate Planning Forum, Treasurer, 2013-Present; Moderator, 2012-2013; Program Chair, 2011-2012; Steering Committee, 2011-Present
  • Massachusetts Bar Association, Probate Law Practice Group, Probate Law Section Council, 2009-2010
  • Greater Boston Fiduciary Law American Inn of Court, Co-Founder, 2016; President, 2016-2018
  • New Hampshire Bar Association
  • Dartmouth Lawyers Association
Honors & Awards
  • Best Lawyers in America, Litigation – Trust & Estates, 2023
  • Boston Magazine, Top Lawyer, Trust & Estates, 2022
  • Chambers High Net Worth guide, Private Wealth Disputes-Massachusetts, 2016-2023
  • Massachusetts Super Lawyers magazine, Estate and Trust Litigation, 2009-2022; Top 100 Attorney, 2016
  • Chambers USA – America's Leading Business Lawyers guide, Leading Litigator, 2010-2013
  • Martindale-Hubbell AV Preeminent Peer Review Rated