Kathleen M. "Katie" O'Sullivan

Seattle, WA Directions

Recognized in Best Lawyers since 2009

Awarded Practice Areas

Appellate Practice Bet-the-Company Litigation Commercial Litigation

*Named the "Lawyer of the Year" in this practice area in the 2026 edition in Seattle.

Lawyer of the Year Badge - 2026 - Appellate Practice

Visit Website

Awarded Practice Areas

Appellate Practice Bet-the-Company Litigation Commercial Litigation

*Named the "Lawyer of the Year" in this practice area in the 2026 edition in Seattle.

Works at

Perkins Coie LLP

212 Best Lawyers awards

Biography

Kathleen M. O'Sullivan is a top attorney recognized by Best Lawyers in the practice area(s) of Appellate Practice, Bet-the-Company Litigation and Commercial Litigation.

Kathleen M., who practices law in Seattle, Washington, has been recognized since 2009. This recognition is based on an exhaustive peer-review survey, reflecting the high esteem in which Kathleen M. is held by other top lawyers in the same geographic and legal practice area.

Locations

Seattle, Washington

206-359-8000

1301 Third Avenue, Suite 4200
Seattle, WA 98101-3099

Education

Georgetown University, J.D., graduated 1996
Yale University, BA

Bar Admissions

Washington, Washington State Bar Association

Affiliations

American Law Institute - Member
Federal Bar Association - Member
Washington State Bar Association - Member

Federal Clerkships

United States Court of Appeals
United States District Court

Client Testimonials

Awards & Focus

Named "Lawyer of the Year" by Best Lawyers^® for:

Appellate Practice, Seattle (2026)
Bet-the-Company Litigation, Seattle (2025)
Appellate Practice, Seattle (2024)
Appellate Practice, Seattle (2016)

Recognized in The Best Lawyers in America^® 2026 for work in:

Appellate Practice
Bet-the-Company Litigation
Commercial Litigation

Special Focus:

Appellate
Civil Litigation
Class Actions
Complex Litigation

Awards:

Co-Recipient of awards for IOLTA Supreme Court litigation (American Bar Association, Washington State Bar Association, King County Bar Association, Perkins Coie)
Listed in Washington Law & Politics, “Washington's Super Lawyers," 2007 - Present

News & Media

Case History

Cases

Other Court Admissions

U.S. Supreme Court
U.S. Court of Appeals for the Ninth Circuit
U.S. District Court for the Western District of Washington
U.S. District Court for the Eastern District of Washington

Your browser is not fully compatible with our automatic printer friendly formatting.

Please use the print button to print this profile page.