Since 1890, there have always been seven Missouri Supreme Court judges, which is the standard number of judges for the state and federal Supreme Court. Only the chief justice is referred to as a justice, and the other members are referred to as judges.
The chief justice is elected to a 2-year term by a vote from the Supreme Court judges. The qualification needed to be a Missouri Supreme Court judge is governed by the Missouri constitution. According to the Missouri State court system, a judge must be at least 30 years old, be licensed to practice law in Missouri, have been a citizen of the US for at least 15 years and have been a qualified state voter for at least nine years.