He grew up working on the family ranch under his father's guidance, which is where he learned horsemanship and developed his early skills as a trainer.

[2]: 19–20  He was also a good competitor as he demonstrated early on in high school playing catcher on a championship baseball team.

[2]: 20 After his service in the Navy, Matlock returned to ranch work and secured his first major job training Quarter Horses at 3D's Stock Farm for W.T.

Howell Ranch in Seagoville, Texas, and "had great influence on both the cutting and Quarter Horse worlds.

[2]: 22  A year later, he purchased a cutting mare named Stardust Desire in partnership with his long time friend George Tyler.

[2]: 22  Matlock continued to show the mare for Woodward and in 1966, the pair won their first NCHA World Championship.

In 1967, Matlock was reunited with Peppy San, the senior sire for Woodward's Douglas Lake Cattle Company.

His third marriage was to Carol Ramsey in 1968, and they resided on Matlock's training and Quarter Horse breeding facility in Gainesville, Texas, where they stood several world champion stallions, including Peppy San and Zan Parr Bar, both of whom were inducted into the AQHA Hall of Fame.

Matlock and Carol hauled together on the show circuit competing in NCHA and AQHA sponsored events throughout the US.