About David O. McColloch

David has devoted his career to helping health care providers and professionals navigate some of the most challenging legal situations. He approaches every case with rigorous investigation, combining a deep, practical understanding of both legal principles and the scientific issues central to his clients’ cases. Known for his collaborative style, David partners closely with clients from the initial notice of a potential claim through trial and appeal, providing comprehensive and strategic representation every step of the way.

David began his legal career as an attorney-examiner with the Pennsylvania Insurance Department, managing more than $200 million of litigation exposure for the Mcare Fund on behalf of physicians and hospitals around the state. In 2018, he moved to private practice. David is experienced in handling litigation in state and federal courts, from investigation and initial pleadings, to discovery, depositions and expert review, through to resolution.

A Pennsylvania native, David is proud to call Delaware County home.

Year joined

2025

Results

Defense verdict Secured on behalf of a major Philadelphia healthcare provider

Health Care Liability
February 20, 2026

We obtained a defense verdict on behalf of a major Philadelphia healthcare provider after a contentious six-day trial. After undergoing a kidney transplant, a patient suffered complications in post-operative care and died a day after the surgery. The plaintiffs were critical of the post-operative care, claiming the physicians failed to take the patient back to the operating room in light of post-op bleeding.

 

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Services

Areas of Law

  • Other 2
    • Health Care Liability
    • Miscellaneous Professional Liability

Practice Details

  • Firm Information
    Position
    Associate
    Firm Name
    Marshall Dennehey
  • Representative Cases & Transactions
    Cases
    Significant Representative Matters: Successfully appealed a seven-figure verdict in a wrongful death lawsuit against a primary care physician accused of failing to prescribe screening tests for liver cancer.
    Secured summary judgment for a physician sued for wrongful death
    accused of participating in another medical practice's fraudulent selling of a cosmetic product as an alternative cancer treatment.
    Successfully defended a plaintiff's appeal of a defense verdict for a primary care physician accused of failing to prescribe preventative treatment for a patient who ultimately suffered a heart attack, in a case where plaintiff's treating cardiologists gave trial testimony against the client.
  • Additional Links

Experience

  • Bar Admission & Memberships
    Admissions
    2015, Pennsylvania
    Memberships
    Montgomery Bar Association.
  • Education & Certifications
    Law School
    University of Wisconsin Law School
    Class of 2014
    J.D.
    Other Education
    Bard College
    Class of 2009
    B.A.

Contact David O. McColloch

Associate at Marshall Dennehey
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620 Freedom Business Center, Suite 300King Of Prussia, PA 19406U.S.A.

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Attorneys FAQs

  • What year was this attorney first admitted to the bar?
    David O. McColloch was admitted in 2015 to the State of Pennsylvania.
  • What year was this attorney's law firm established?
    Marshall Dennehey was established in 1962.