Trejo emerged from a childhood marked by crime and incarceration, achieving sobriety during his mid-twenties before transitioning into film work. Beginning as an extra and boxing trainer in 1985, he quickly accumulated roles across hundreds of productions, establishing himself as a fixture for characters requiring an intimidating, hardened appearance. His distinctive prison tattoos and muscular build made him instantly recognisable and repeatedly cast as criminals or gang members, often appearing without clothing to showcase his body art.

The 1987 film 'Death Wish 4: The Crackdown,' featuring Charles Bronson, provided Trejo with an unusual milestone—the opportunity to wear formal business attire rather than appear bare-chested. This modest costume change symbolised professional advancement to the actor, marking what he describes as validation of his established position in the industry. Now well into his eighties, Trejo remains active in the entertainment industry with an extensive lineup of future roles, maintaining the pragmatic work ethic that has defined his decades-long career.