John P. O'Connor

Kansas City, MO

About John P. O'Connor

Kansas City Business Journal “Best of the Bar” Kansas City’s Top Attorneys chosen by their peers Best Lawyers in America Criminal Defense: General Practice & White Collar Crime 2005-2026 Best Lawyers in America’s Kansas City, MO Criminal Defense: Non-White Collar Crime “Lawyer of the Year” John O’Connor's practice is focused on criminal law, white collar criminal defense, and complex criminal litigation in both state and federal courts. He began his law career as an assistant prosecuting attorney in Jackson County, Missouri. He was promoted to trial director where he supervised 40 attorneys and handled a major felony criminal trial docket. In that role, he prosecuted major crimes and oversaw attorneys handling hundreds of criminal cases each year.

In 1987, John entered private practice. For more than 35 years, he has been recognized by his peers and news publications as one of Kansas City's top criminal defense attorneys. He has tried cases before juries in federal and state courts in Kansas and Missouri, including numerous high profile and complex matters as well as death penalty cases. His cases have received news coverage locally and nationally.

A case he defended that became known as the “FBI Sting Murder Trial was aired nationally on Court TV. After listening to John's closing argument, Nancy Grace gave him an A+. See below for a list of John's other notable representations.

Proven verdicts and settlements at Wagstaff & Cartmell

These results are credited to Wagstaff & Cartmell. A result appears under an attorney's own name only when a published source names them as counsel on the case.

San Francisco Unified School District's case was the first JUUL bellwether trial against Altria; after the plaintiffs rested, Altria agreed to pay $235 million to resolve roughly 6,000 pending e-vapor claims nationwide.

U.S. District Court, Northern District of California (MDL No. 2913) · 2023Product LiabilityRead the full story →
$20 millionVerdictTop 20 in Indiana · #12

A federal jury in Hammond, Indiana found that Ethicon's Prolift transvaginal mesh was defectively designed and inadequately warned against, awarding Barbara and Anton Kaiser $35 million. A judge reduced the punitive damages, leaving a $20 million verdict that the Seventh Circuit affirmed in full in 2020.

U.S. District Court, N.D. Indiana, No. 2:17-cv-114 · 2018Product LiabilityRead the full story →

Kathryn Gant died at the scene of a head-on crash on K-58 in Kansas on June 10, 2011, after a driver crossed the center line in a no-passing zone. Her husband sued the driver, the driver's parents and the family oil company. After a five-day bench trial in June 2015, a Coffey County judge found all of them liable and awarded $6,723,021. Under a pretrial agreement, none of the judgment could be collected from the defendants themselves.

Coffey County District Court, Kansas · 2015Wrongful DeathRead the full story →
$6 millionVerdict

A Los Angeles jury found Meta and Google's YouTube negligent in designing platforms that harmed a young woman identified as K.G.M., who began watching YouTube at age 6 and joined Instagram at 9. On March 25, 2026, it awarded $3 million in compensatory damages, split 70 percent to Meta and 30 percent to YouTube, plus $3 million in punitive damages. It was the first bellwether trial in the coordinated California social media addiction cases.

Superior Court of California, Los Angeles County (JCCP 5255, Judge Carolyn Kuhl) · 2026Product LiabilityRead the full story →
$5.7 millionVerdict

A Kern County jury handed Coleen Perry a $5.7 million verdict against Johnson & Johnson's Ethicon unit on March 5, 2015, in the first trial ever to reach a jury over Ethicon's TVT-Abbrevo polypropylene mesh sling.

Superior Court of California, Kern County · 2015Product LiabilityRead the full story →

Prior results do not guarantee a similar outcome. Each case is unique and depends on its own facts.

Education

University of Missouri-Kansas City School of Law
J.D., 1982
Avila College
Undergraduate

Bar admissions & credentials

State Bar of Kansas
State Bar of Missouri

Other attorneys at Wagstaff & Cartmell

View firm →

Proven verdicts and settlements from other Kansas City firms

Dollar, Burns, Becker & Hershewe
Dollar, Burns, Becker & Hershewe
$82.3 Million Verdict for I-70 Crash Victim Struck by Trucker Watching Videos on iPad
The Popham Law Firm
The Popham Law Firm
$57 Million Settlement for 1,700 Sprint Workers in Landmark ADEA Collective Action
Brown & Crouppen
Brown & Crouppen
$119.5 million · $462 Million Verdict After Fatal Underride Crash Killed Two Young Fathers
Shamberg Johnson & Bergman
Shamberg Johnson & Bergman
$15.28 million · $23.5 Million Verdict Against Swift Transportation for Meth-Impaired Driver
Cullan & Cullan LLC
Cullan & Cullan LLC
$20.82 million · $25.4 Million Verdict for Birth Injury From Excessive Pitocin

Prior results do not guarantee a similar outcome. Each case is unique and depends on its own facts.