Peter D. Sullivan
Peter D. Sullivan
Chairman
He/Him
"Everything I do is driven by what’s best for my clients."

Peter D. Sullivan
Chairman
He/Him
"Everything I do is driven by what’s best for my clients."
About Peter
Peter has spent over 40 years navigating complex professional liability and commercial litigation, often managing cases with significant exposure. His experience defending attorneys, accountants, and financial institutions reflects practical insight and a balanced view of risk.
Peter has held numerous leadership roles at the firm before becoming Chairman in 2019. Since then, his visionary approach, enthusiasm, and decisive leadership have been central to the firm's growth in existing and new markets, as well as to strengthening client service, talent, efficiency, and profitability. He is a strong advocate for diversity, equity, and inclusion (DEI) and fosters a firm culture built on professionalism and mutual respect.
Areas of Focus
Experience
- In 2025, successfully convinced an Illinois Appellate Court to affirm our summary judgment win in favor of a law firm client in a legal malpractice action arising out of commercial litigation over ownership, control, and alleged mismanagement of an Illinois LLC.
- In 2025, obtained complete defense verdict in New York jury trial of malpractice claims against national accounting firm, with over $30 million in potential exposure.
- In 2025, obtained summary judgment on legal malpractice claims in Cook County, Illinois, against regional law firm involving over $10 million in claimed damages.
- In 2024, obtained complete dismissal of claims against attorneys for malpractice and fraud in DuPage County, IL based on absolute litigation privilege, affirmed on appeal in 2025.
- In 2024, secured a complete defense arbitration award in representation of a law firm client in a bet-the-firm legal malpractice claim arising out of an underlying patent infringement case.
Recognition
- The Best Lawyers in America®, Commercial Litigation, 2016 – 2026
- Illinois Super Lawyers, 2005 – 2025
- Crain's Chicago Business, Notable Leader, Accounting, Consulting & Law, 2024
- Leading Lawyers, Top 10 Illinois Legal Malpractice Defense, 2018
- Illinois Jury Verdict Reporter, Trial Excellence Award, Defense – Attorney Malpractice, 2011
- Martindale-Hubbell, AV® Peer Review Rating
- Leading Lawyer, Commercial Litigation; Insurance, Insurance Coverage & Reinsurance Law; Products Liability Defense Law; Professional Malpractice Defense Law
Credentials
Education
- Loyola University Chicago School of Law, JD, with honors, 1983
- University of Notre Dame, BA, 1980
Bar Admissions
- Illinois
Court Admissions
- US Court of Appeals for the Seventh Circuit
- US District Court for the Central District of Illinois
- US District Court for the Northern District of Illinois, including Trial Bar
- US District Court for the Southern District of Illinois
- US District Court for the Eastern District of Michigan
- US District Court for the Western District of Michigan
- US District Court for the Western District of Wisconsin
Thought Leadership
Presentations
- Moderator, "Year in Review: Significant Developments in Legal Malpractice Cases of 2024," Hinshaw's 24th Annual Legal Malpractice & Risk Management (LMRM) Conference, Chicago, Illinois, March 5, 2025
- Opening Remarks, "60 Million Congress," Global Polonia Summit, Chicago, Illinois, October 19, 2024
- "The Year in Review 2023 – Significant Attorney Malpractice and Ethics Decisions," Hinshaw’s 23rd Annual Legal Malpractice & Risk Management (LMRM) Conference, Chicago, Illinois, March 6, 2024
- "Lessons from the Professional Liability Front: Claims CAN Happen to You," ICPAS Midwest Accounting Show, Rosemont, Illinois, August 23, 2016
Event
- Justyna Regan and Peter Sullivan to Present at the Global Polonia Summit, October 18-19, 2024
In The News
Press Releases
- 102 Hinshaw Lawyers Recognized in 2026 Editions of The Best Lawyers in America® and Ones to Watch™, Aug 21, 2025
- Hinshaw Celebrates the Firm's 90th Anniversary, Sep 20, 2024
- Peter Sullivan and Scott Seaman Selected as Crain’s Chicago Business 2024 Notable Leaders in Law, Sep 9, 2024
- 105 Hinshaw Lawyers Recognized in 2025 Editions of Best Lawyers in America and Ones to Watch, Aug 15, 2024
- Peter Sullivan Re-elected Chairman of Hinshaw & Culbertson LLP, Jun 3, 2024
Interests
Did you know...
Outside of the office, Peter enjoys spending time with his twelve siblings, his wife Sheli, their five children, and grandson. He also enjoys golfing, running, skiing, hiking, and supporting all Chicago sports teams.
Thought Leadership
Presentations
- Moderator, "Year in Review: Significant Developments in Legal Malpractice Cases of 2024," Hinshaw's 24th Annual Legal Malpractice & Risk Management (LMRM) Conference, Chicago, Illinois, March 5, 2025
- Opening Remarks, "60 Million Congress," Global Polonia Summit, Chicago, Illinois, October 19, 2024
- "The Year in Review 2023 – Significant Attorney Malpractice and Ethics Decisions," Hinshaw’s 23rd Annual Legal Malpractice & Risk Management (LMRM) Conference, Chicago, Illinois, March 6, 2024
- "Lessons from the Professional Liability Front: Claims CAN Happen to You," ICPAS Midwest Accounting Show, Rosemont, Illinois, August 23, 2016
Event
- Justyna Regan and Peter Sullivan to Present at the Global Polonia Summit, October 18-19, 2024
In The News
Press Releases
- 102 Hinshaw Lawyers Recognized in 2026 Editions of The Best Lawyers in America® and Ones to Watch™, Aug 21, 2025
- Hinshaw Celebrates the Firm's 90th Anniversary, Sep 20, 2024
- Peter Sullivan and Scott Seaman Selected as Crain’s Chicago Business 2024 Notable Leaders in Law, Sep 9, 2024
- 105 Hinshaw Lawyers Recognized in 2025 Editions of Best Lawyers in America and Ones to Watch, Aug 15, 2024
- Peter Sullivan Re-elected Chairman of Hinshaw & Culbertson LLP, Jun 3, 2024
Peter's Insights

Press Release
Aug 21, 2025
102 Hinshaw Lawyers Recognized in 2026 Editions of The Best Lawyers in America® and Ones to Watch™

Event
October 18-19, 2024
Justyna Regan and Peter Sullivan to Present at the Global Polonia Summit

Press Release
Sep 9, 2024
Peter Sullivan and Scott Seaman Selected as Crain’s Chicago Business 2024 Notable Leaders in Law

Press Release
Aug 15, 2024
105 Hinshaw Lawyers Recognized in 2025 Editions of Best Lawyers in America and Ones to Watch

Press Release
Jun 3, 2024
Peter Sullivan Re-elected Chairman of Hinshaw & Culbertson LLP

Press Release
Apr 18, 2024
Hinshaw Makes "Big Gains" in 2023 as Firm Sees Double-Digit Revenue and Profit Growth

Press Release
Aug 17, 2023
101 Hinshaw Lawyers Recognized in 2024 Editions of Best Lawyers in America and Ones to Watch

Press Release
Mar 9, 2023
Hinshaw Announces Adler Murphy & McQuillen LLP Will Join the Firm

Press Release
Feb 1, 2023
Hinshaw Expands Texas Presence with New Dallas Office and a Team of Financial Services Attorneys