Trevino was born in Dallas, Texas in poverty to parents of Mexican descent, and spent his childhood attending school occasionally and helping earn money for the family. He was introduced to the game of golf at eight years old, when he began caddying at a local golf course. The caddies had three short practice holes behind their shack, and it was there, with old, discarded clubs, that Trevino learned to play the game of golf. At seventeen, Trevino join the United States Marine Corps and served four years. Over the last eighteen months in the service, a great deal of his time was spent playing golf with Marine Corps officers.
After his discharge, Trevino continued his pursuit of the game, spending years working on his game. In 1967, he began playing on the PGA Tour. Over the course of his career, Trevino has won 29 tournaments, including five majors. He currently plays on the Champions Tour, formerly known as the Senior PGA TOUR.