The step son of the hot tempered Roy Eversole, Parker served in the Vietnam War after school. Following the war Parker eventually became a member of the Sparta police department, working for Bill Gillespie. When Virgil Tibbs came to work for the department he was uncertain about the new chief detective but came to put aside his doubts as Virgil became a valued member of the police force, and counted Virgil and his wife Althea as friends.
Parker was a sensitive person who cared deeply about the people of Sparta and many of the people living in the area. He was often assigned to dispatcher duty and spent many shifts working the desk at the station, fielding calls from a variety of people. He would often be given patrol shifts, and maintained a friendly demeanor when working with the public. When working at the station he would often have a mason jar filled with sweet tea sitting on his desk. At times Parker would make coffee for the station, however Gillespie was less than thrilled with the results. Parker was very loyal to his friends both in and outside the department, and it pained him greatly when a fellow officer was injured or killed in the line of duty.
As an officer with the department Parker took his duties very seriously, sometimes to a fault. When the department got a speed radar Parker was given the opportunity to use it, however his over zealous behavior with the speed gun caused a large number of city residents to become upset with him. Gillespie eventually ordered the radar be taken away from Parker before he wound up pulling over an ambulance.
In 1994 Parker was promoted to the rank of Sergeant and was a senior member of the police force. That year a number of changes took place as Gillespie's contract was controversially terminated and Tibbs graduated from law school and left the department to begin a new career as an attorney. Parker continued to serve the Sparta PD, working as well for the new Chief Forbes as he did for Gillespie.
- Parker Williams was played by David Hart for all seven seasons of the show as well as in the television movies.