Patrick Campbell

Joe is the chair of the firm’s Litigation Practice Group. He manages a variety of complex cases involving software class actions, real estate, products liability, banking, intellectual property, and anti-trust matters. He has extensive experience representing both large and small plaintiffs and defendants in challenging civil litigation. He has been selected as a member of the Wisconsin Super Lawyers for six years in a row. Prior to joining O’Neil Cannon, Joe was an associate at t...

Brion T. Winters is a top attorney recognized by Best Lawyers in the practice area(s) of Real Estate Law. Brion T., who practices law in Milwaukee, Wisconsin, has been recognized since 2027. This recognition is based on an exhaustive peer-review survey, reflecting the high esteem in which Brion T. is held by other top lawyers in the same geographic and legal practice area.

Philip Tallmadge is a top attorney recognized by Best Lawyers in the practice area(s) of Litigation - Insurance, Personal Injury Litigation - Defendants and Product Liability Litigation - Defendants. Philip, who practices law in Milwaukee, Wisconsin, has been recognized since 2025. This recognition is based on an exhaustive peer-review survey, reflecting the high esteem in which Philip is held by other top lawyers in the same geographic and legal practice area.

Michael J. Cerjak is a top attorney recognized by Best Lawyers in the practice area(s) of Personal Injury Litigation - Plaintiffs. Michael J., who practices law in Milwaukee, Wisconsin, has been recognized since 2020. This recognition is based on an exhaustive peer-review survey, reflecting the high esteem in which Michael J. is held by other top lawyers in the same geographic and legal practice area.

Nathan K. Johnson is a top attorney recognized by Best Lawyers in the practice area(s) of Litigation - Trusts and Estates, Nonprofit / Charities Law, Tax Law and Trusts and Estates. Nathan K., who practices law in Waukesha, Wisconsin, has been recognized since 2019. This recognition is based on an exhaustive peer-review survey, reflecting the high esteem in which Nathan K. is held by other top lawyers in the same geographic and legal practice area.

William D. Gardner is a top attorney recognized by Best Lawyers in the practice area(s) of Bankruptcy and Creditor Debtor Rights / Insolvency and Reorganization Law and Litigation - Bankruptcy. William D., who practices law in Milwaukee, Wisconsin, has been recognized since 2027. This recognition is based on an exhaustive peer-review survey, reflecting the high esteem in which William D. is held by other top lawyers in the same geographic and legal practice area.

Background Mr. Prachthauser was born in Milwaukee, Wisconsin, on January 7, 1951. Prior to joining the firm, he was House Counsel for Employers Insurance of Wausau. He is married to Joan Marie, and they reside in Hartland, Wisconsin. He has two daughters, Emily and Tracy. Lectures Mr. Prachthauser is a frequent presenter and speaker for the State Bar of Wisconsin, American Board of Trial Advocates, and Wisconsin Academy of Trial Lawyers. He has been a Civil Trial Practice Instructor at the Un...

Mark Foley is a Shareholder with more than 40 years experience meeting the complex business and legal needs of clients ranging from individual business owners to industry trade associations and Global 500 companies. Mark has successfully tried cases before judges and juries in federal and state courts, represented debtors and creditors in bankruptcy courts throughout the United States, and arbitrated matters before AAA and NASD panels. He has directed and conducted the nationwide defense of r...

Leila Sahar is a top attorney recognized by Best Lawyers in the practice area(s) of Commercial Litigation. Leila, who practices law in Milwaukee, Wisconsin, has been recognized since 2026. This recognition is based on an exhaustive peer-review survey, reflecting the high esteem in which Leila is held by other top lawyers in the same geographic and legal practice area.

Grant Killoran is a shareholder at O’Neil Cannon and the past Chair of its Litigation Practice Group. He has significant and diverse trial experience representing clients in Wisconsin State and Federal Courts, and courts around the country, focusing on complex business, health care and employment law disputes. Grant also devotes a portion of his practice to arts and entertainment law, with an emphasis on the music industry. Grant is listed in The Best Lawyers in America in the practice ...