Beginning in 1949 Martin was lead vocalist for Bill Monroe's Blue Grass Boys. Martin's high voice mixed with Monroe's tenor came to be known as the "high lonesome" sound. His influence radically changed Monroe's music from the fast-paced but smooth style of the "original" 1945 band with Flatt and Scruggs. Martin challenged Monroe to raise the pitch on many of his classics and to write new, "lonesome" songs. This band with Rudy Lyle (banjo) and Charlie Cline (fiddle) was one of the many high points of Monroe's career. Martin's lead was defining in "lonesome" songs such as "Sitting Alone in the Moonlight", "Memories of Mother and Dad" and "I'm Blue, I'm Lonesome".