Glenn Miller be mentored by other professional musicians. In the beginning, he was the main trombone soloist of the band. But when Jack Teagarden joined Pollack's band in 1928, Miller found that his solos were cut drastically. He realized that his future was in arranging and composing. He had a songbook published in Chicago in 1928 entitled "Glenn Miller's 125 Jazz Breaks for Trombone" by the Melrose Brothers. During his time with Pollack, he wrote several arrangements. He wrote his first composition, "Room 1411", with Benny Goodman, and it was released as a 78 by Brunswick Records under the name Benny Goodman's
Sometime (Glenn Miller song) 6101. The liner notes for the album by Brad McCuen described the song as follows: "Glenn and his close friend Chummy MacGregor, the band's pianist, collaborated on this quality pop song. It is a mystery why Glenn did not include this song among the hundreds he later recorded. Ray Eberle has the vocal." The version included was the April 18, 1939 performance at the Meadowbrook. There were five broadcast performances of “Sometime” by Glenn Miller and his Orchestra in 1939. It is Score 117 in the library and the composer credits are listed as Glenn Miller and John Chalmers MacGregor.