The show is centered on Cordell Walker, a Dallas Fort Worth-based member of the Texas Rangers, a state-level bureau of investigation. Walker was raised by his paternal uncle, a Native American named Ray Firewalker, who served in the Marines in Special Forces in the Vietnam War, and shares the values of sheriffs in the Wild West.
His partner and best friend is James "Jimmy" Trivette, a former Dallas Cowboys player who takes a more modern approach. Walker's young partner grew up in Baltimore and used football as his ticket to college education which led to his career, until one day when he tore his shoulder. Trivette also works inside the office using computers and cellular phones to collate information of the people who've been taken into custody. After Walker's original partner died unexpectedly, and all thanks to C.D.'s pleasure in finding a replacement partner for Walker, he didn't believe in Trivette, but was later taken in, as the two grew to bond with each other.
Walker also works closely with Alexandra "Alex" Cahill, a Tarrant County Assistant District Attorney, who on occasion puts up a frown if Walker doesn't obtain results in time. He also gets advice on cases from C.D. Parker, a veteran Ranger who worked with Walker until retiring to operate a small restaurant and bar called "CD's Bar and Grill."