In 2002, he started The Mills Firm to focus exclusively on appellate litigation. As his practice grew, he took on partners to develop a firm that was known variously over the years as Mills & Carlin, Mills & Creed, and Mills Creed & Gowdy.
In 2010, he left that firm to restart The Mills Firm and shift his practice to Tallahassee, home of the two courts in which he most often appeared at the time: the Supreme Court of Florida and the First District Court of Appeal. With an emphasis on constitutional and personal injury litigation, The Mills Firm flourished and grew.
In 2019, he decided to return to his commercial litigation roots in Jacksonville and expand his firm’s depth and ability to provide more robust trial support services by joining forces with his friends at the former Tanner Bishop commercial litigation boutique to form Bishop & Mills, now known as Bishop Page & Mills. Despite the renewed emphasis on commercial litigation, John continues to handle constitutional and personal litigation, especially defending significant plaintiff’s judgments on appeal. He moved back to Jacksonville in 2020.
John has served as appellate counsel in two major cases decided by the Supreme Court of the United States. He served as lead counsel in a 2004 immigration rights case that ended the indefinite detention of over 2,000 Cubans who came to this country in the Mariel Boatlift. The case was also unique in that John became the last attorney to answer a question from the bench from Chief Justice Rehnquist, and it also features a rare split with Justice Scalia writing the majority opinion, and Justice Thomas the dissent. Clark v. Martinez, 543 U.S. 371 (2005). John also assisted his then partner in the landmark 2010 case that invalidated life without parole sentences for juveniles who did not kill anyone. Graham v. Florida, 560 U.S. 48 (2010).
He has argued and won many ground-breaking cases in the Florida Supreme Court on behalf of the League of Women Voters and Common Cause and on behalf of plaintiffs in multi-million dollar lawsuits against the cigarette industry. He served as lead post-conviction counsel on a twelve-year journey including a three-week evidentiary hearing and multiple appeals to the Florida Supreme Court culminating in the exoneration of a wrongfully convicted innocent man on Florida’s death row. He has been lead counsel in hundreds of appeals in the lower appellate courts, including the United States Court of Appeals for the Eleventh Circuit and Florida’s district courts of appeal. He has also served as special counsel to the Florida Judicial Qualifications Commission in the successful prosecution of judicial misconduct charges against four Florida judges.
John has served in a number of leadership positions in the legal profession. He is currently the Amicus Chair and member of the board of directors for the Florida Justice Association He has chaired the Appellate Practice Certification Committee and the Appellate Court Rules Committee of The Florida Bar, and served on the executive committee of the bar’s Appellate Practice Section. He is a master in the Chester Bedell Inn of Court and an alumnus (originally a founding master) of the First District Appellate American Inn of Court. He served for several years on the Board of Trustees of the Florida Supreme Court Historical Society and the board of governors of the Jacksonville Bar Association.
His professional awards include the 2023 Jon E. Krupnick aware from the Florida Justice Association for “relentless commitment, perseverance and fortitude to seek justice and achieve success through all obstacles and legal roadblocks,” both the 2022 and 2005 John R. Hamilton Pro Bono Award from the Appellate Practice Section (an award named for one of his early mentors), the 2006 S. Victor Tipton Award from the Florida Justice Association for “superior achievement in legal writing and commitment,” and the 2006 Florida Bar President’s Pro Bono Service Award for the Fourth Judicial Circuit.
He has lectured on advanced appellate topics at numerous conferences and seminars, including the Eleventh Circuit Judicial Conference, the Eleventh Circuit Appellate Practice Institute, the Florida Appellate Justice Conference, and the Florida Bar Appellate Practice Certification Review Course, where he taught federal appellate practice for several years to Florida appellate lawyers preparing to sit for the board certification exam.
Finally, Mr. Mills is a leader in the community. He supports various non-partisan and progressive movements in Jacksonville, including the Northside Coalition, Take ‘Em Down Jax, and the movement to rename Jacksonville schools that had been named for leaders of the Confederacy. He has also been active in supporting Democratic candidates for national, state, and local government, including providing voter-protection work for the Democratic nominee’s campaigns in the past five presidential elections. He is an alumnus of Leadership Jacksonville and was recognized as a “40 Under 40” top business leader in the community by the Jacksonville Business Journal. The media often turn to him both for background and on-the-record comment on various legal issues of public interest.