As an attorney, Cordonnier represented litigants in dozens, and likely over 100 mediated cases prior to taking the bench. He was first formally trained in mediation in 2007 and after that served as a civil mediator in cases prior to taking the bench. In 2022, he again completed formal mediation training at the University of Missouri-Kansas City.
In 2008, Cordonnier was appointed Greene County Circuit Judge. He was elected to judicial office that same year. Subsequently, he was retained in 2012 and 2018 and served until his retirement from the bench in 2023. In his first retention election, Judge Cordonnier earned the highest Judicial Performance Evaluation score among all Circuit and Appellate Judges retained in the state. His fellow judges awarded him a perfect score, recognizing his exceptional skill and dedication to his profession.
While serving as a Circuit Judge, Judge Cordonnier was elected by his peers statewide to serve as President of the Missouri Circuit Judges’ Association in 2015-2016. The association represents all Circuit Judges in current events and as a liaison to the Missouri Supreme Court and the Missouri Legislature.
In 2016 Judge Cordonnier was elected to serve as the Presiding Judge of the 31st Judicial Circuit Court, an office he held until stepping down pending retirement. Upon election as the Presiding Judge, Judge Cordonnier was appointed by the Missouri Supreme Court to serve as a member of the Presiding Judges’ Executive Committee. The PJEC is a group of 12 Presiding Judges from throughout the state that serve as the liaison between the Circuit Court’s Presiding Judges and the Missouri Supreme Court.
Throughout his tenure, Judge Cordonnier worked with other judges and elected officials to obtain legislative authorization for an additional Family Court Commissioner position in Greene County, strengthening the court’s ability to handle family-related cases effectively. Again, with other judges and elected representatives, Judge Cordonnier was instrumental in legislation that authorized Greene County to gain two additional Associate Circuit Judicial positions. Finally, in 2017, with Judge Cordonnier’s leadership, legislation was passed awarding Greene County an additional Circuit Judge, the first such judicial position to be added in 40 years. The addition of these judicial officers reinforced the ability of the Court to provide timely and efficient justice in Greene County.
To further enhance his expertise in the legal field, Judge Cordonnier participated in several specialized programs. He completed the Advanced Science and Technology Adjudication Resource (ASTAR) program sponsored by the US Department of Justice. This two-year program focused on scientific and technical matters in judicial proceedings, and as a result, Judge Cordonnier became ASTAR certified. He was then nominated a fellow in the National Courts and Science Institute (NCSI).
In addition, Cordonnier was invited by the Supreme Court to participate in specialized training in the management of Complex Litigation. This training equipped and qualified him to manage complex cases pending in the trial courts.
Lawyers filing new cases, anticipating unusual scientific, technical, or complex issues, may request the special assignment of either an ASTAR-certified judge, or a Complex Litigation certified judge. This further ensures the court’s expertise in handling cases with extraordinary issues. Based on these certifications and his trusted reputation, Judge Cordonnier was appointed by the Supreme Court to preside over numerous cases in many judicial circuits throughout Southern Missouri.
Judge Cordonnier's commitment to continuous learning and professional development is evident in his participation in programs such as the Missouri Court Management Institute (MCMI), a comprehensive training program on court management facilitated by the National Judicature Society. He completed the two-year program, enhancing his skills and knowledge in effectively managing the court as an entity. In addition, he was invited to attend the Judicial Leadership Program initiated by the Supreme Court. highlighting his exemplary leadership qualities, dedication to his role as a judge and further underscoring his reputation as a respected and influential judicial figure.
Within Greene County, Judge Cordonnier has undertaken numerous responsibilities, including chairing various committees, including those searching for new commissioners, implementing electronic case management, negotiating with the county commission for additional courtroom space, rewriting local court rules, actively managing the COVID challenges, and serving as Greene County Probate Judge from 2010-2023.
In 2016, Judge Cordonnier was awarded the JUDICIAL EXCELLENCE AWARD. The SMBA award recognizes a judge who exemplifies the highest legal and ethical standards to which all in the legal profession should strive and are actively involved in service to both the legal and non-legal community. This award is made no more often than every 5 years.
In 2022, Judge Cordonnier was awarded the DISTINGUISHED ATTORNEY AWARD. The SMBA award recognizes a member of the bar who has exhibited exemplary standards in the practice of law for 20 or more years, whose practice of law epitomizes the highest legal and ethical standards to which all attorneys should strive, and who has actively served both the legal and non-legal community. The Distinguished Attorney Award is the highest honor bestowed by the SMBA.
Judge Cordonnier's dedication to legal and judicial education is evident through his participation in various conferences and programs. He has been a presenter at the Annual Judicial College, a speaker at the Presiding Judges’ Conference, a speaker at the Annual Meeting of the Missouri Bar, and a contributor to the Advanced Trial Skills Seminar designed for judges. He was the author of the CLE practice series update “Automobile Torts.” Finally, he has participated in innumerable seminars and panels related trial practice, evidence, jury instructions, punitive damages, and other related topics. His commitment to continuous learning and staying abreast of legal developments underscores his commitment to excellence in the legal profession.
Judge Michael J. Cordonnier's exemplary career and significant contributions to the legal profession have left an indelible mark on the 31st Judicial Circuit Court. His dedication to justice, leadership, and involvement in numerous committees and organizations has resulted in notable improvements in the court system and relationships with legislators. Judge Cordonnier's expertise, professionalism, and unwavering commitment to serving the community make him a highly respected and influential figure in the legal field. As he continues his work in alternative dispute resolution, his impact on the judicial system and dedication remain unwavering.