About John
John Cannon built his legal foundation over a series of academic steps. He earned a Bachelor of Arts in English from the University of Kansas in 2002. He went on to law school at Oklahoma City University, completing a J.D. in 2010. After several years in practice he attended the Judge Advocate General’s Legal Center and School in 2013, where he received training in military law and practice.
Cannon’s early career moved quickly through several public service roles. In 2010 he began as an assistant district lawyer in Garfield County. The following year he joined the Oklahoma County Public Defender’s Office as an assistant public defender, handling criminal defense on behalf of indigent clients. In 2013 he entered the Judge Advocate General’s Corps and served as a judge advocate. He later took a post in the Oklahoma Attorney General’s Office as an assistant lawyer general in 2016. In 2018 he left government employment to open his own practice, Cannon Law Office, PLLC.
Those roles gave Cannon a mix of courtroom experience and government-side work. He moved between prosecution-adjacent roles, defense work and military legal practice. He is admitted to practice in state court in Oklahoma and holds federal admissions in the Western, Eastern and Northern Districts of Oklahoma, as well as the Tenth Circuit. He has maintained membership in the Oklahoma State Bar since 2010 and belongs to professional groups that include the Oklahoma Criminal Defense Lawyers Association, the William J. Holloway American Inn of Court and the Tenth Circuit Bar Association.
Colleagues and clients are likely to encounter in Cannon a lawyer used to shifting contexts. He has written and argued motions in state and federal settings, appeared in public-defense dockets and performed legal duties consistent with service as a judge advocate. That mix gives him practical familiarity with criminal procedure, trial practice and issues that arise when military service intersects with criminal and administrative law.
He runs Cannon Law Office, PLLC, a firm he founded in 2018. The office handles matters across state and federal forums and continues to represent clients in criminal defense, military law matters and related federal court work. His current practice focuses on criminal defense, military legal representation and litigation in Oklahoma state and federal courts.
