He was portrayed by the late Andy Griffith, who had earlier portrayed Sheriff Andy Taylor. In the 1991 episode The Dame and 1993 episode The Diner a young Matlock was portrayed by Steve Witting.

Matlock was a graduate of Harvard Law School, and worked a number of years as a public defender. He later went in to private practice, where he normally charged $100,000 to defend an individual. However if he was convinced the person was innocent or if the person could not pay right away or at all, Matlock would allow people to pay over time or even waive the fee. Once he took a case Matlock and his team would work to uncover the truth, and were able to win acquittals for his clients while ensuring the actual guilty party faced justice.

He lived in suburban Atlanta, in a modest farmhouse. He was noted for his spend thrift ways, and his love of gray suits, preferring to wear those most times. Matlock claimed his spend thrift ways and fondness for hot dogs was due to losing his savings by investing in 8-track cartridges, and he had to get by on cheap suits and hot dogs.