Thelsey joined the entertainment scene in 1964, he became known as a talented upright bass guitar player for a jazz band called, “The Jazz Rebellion”. Intrigued with the music he learned to play several instruments like the piano, lead and rhythm guitar, as well as all percussion. With a variety of instruments in his repute, Thelsey moved on from “The Jazz Rebellion” to formulate his first singing group called, “ Inquisitive Ones. The “Inquisitive Ones” went on winning first place at multiple local talent shows. During the mid 80’s Thelsey was a member of some of the hottest R&B bands throughout Southern California. The most notable band Thelsey created during that time was called, “Excalibur” whom he played with for more than ten years. During Excalibur’s lifespan, he wrote, produced, and recorded all the songs. Excalibur went on to travel and perform for the United States Air Force musical talent show. In addition, Excalibur also won the battles of the bands three years in a row. As the music evolved Thesley then created a more modern singing group known as “Insight” where he wrote and produced multiple albums. The group of three included his wife, best friend, and himself. There was also a subgroup to “Insight” which produced rap and hip-hop artists under Thelsey’s leadership. Thelsey was involved with youth education Insight performed one of their hit songs “Educate Your Mind” which was often requested for Insight to perform. In 2006 Thelsey went on to create his own record label called, “Bully Mic Records” aka “Camp Bully”. The label included 13 artists with a variety of talents from singing, rapping, to writing. Thesley was not only the CEO but he was also the executive music producer.