Lopez formed his first band in Wichita Falls, Texas, at the age of 15. In 1958, at the recommendation of Buddy Holly, Trini and his group "The Big Beats" went to Producer Norman Petty in Clovis, New Mexico. Petty secured a contract for them with Columbia Records, which released the single "Clark's Expedition"/"Big Boy", both instrumental. Lopez left the group and made his first solo recording, his own composition "The Right To Rock", for the Dallas-based Volk Records, and then signed with King Records in 1959, recording more than a dozen singles for that label, none of which charted. In late 1962, after the King contract expired, Lopez followed up on an offer by Producer Snuff Garrett to join the post-Holly Crickets as vocalist. After a few weeks of auditions in Los Angeles, that idea did not go through. He landed a steady engagement at the nightclub PJ's, where his audience grew quickly. He was heard there by Frank Sinatra, who had started his own label, Reprise Records, and who subsequently signed Lopez.