"The steering wheel wasn't moving and the flames started to come in on the floorboard down at his feet where his legs were trapped," Martin told KXAS-TV. "I was aware of the danger. I really wasn't scared."
After several attempts, Martin was able to move the dash panel, free Pierce's leg and pull him from the burning truck. Pierce was airlifted to a Dallas hospital and was in good condition Thursday afternoon, according to WFAA-TV.
Martin was checked out by paramedics on scene, but was uninjured and was able to finish his shift.
The humble deputy told local media he doesn't consider himself to be a hero.
"I think I got lucky and I was in the right place at the right time to be able to help him," Martin said. "I know many other deputies here would do the same thing."