Judge Greg Mathis was born in Detroit, Michigan, and was a member of the Errol Flynns street gang in the 1970s. His gang activities led to police arresting him several times. He worked at McDonald's after his release from jail and later attended Eastern Michigan University, where he led voter registration and Free South Africa campaigns. He was also a member of the Alpha Phi Alpha fraternity.
Greg Mathis graduated from the Ypsilanti campus of Eastern Michigan University with a Bachelor of Science degree in Public Administration. He graduated from the University of Detroit Mercy with a law degree in 1987, but Michigan denied him a law license for several years after graduation because of his criminal history. He became the youngest judge in Michigan in 1995 when he was elected to Michigan's 36th District, and he filled the position for five years.
Greg Mathis met his wife Linda while they were both students at Eastern Michigan University. They have four children, including Jade, born in 1985; Camara, born in 1987; Greg Jr., born in 1989; and Amir, born in 1990.
The "Judge Mathis" television show premiered on September 29, 1999. Judge Greg Mathis is the longest-serving African-American court show judge, ahead of Judge Joe Brown. He is also the second-longest serving court show arbitrator, behind Judith Sheindlin of "Judge Judy."