Gray's time with the Glenn Miller Orchestra produced many of the most recognizable and memorable recordings of the era. He arranged "Elmer's Tune", "Moonlight Cocktail", "Perfidia", and "Chattanooga Choo-Choo" among others, while his compositions included "Sun Valley Jump", "The Man in the Moon", "Caribbean Clipper", "Pennsylvania 6-5000", "I Dreamt I Dwelt in Harlem", "Introduction to a Waltz" with Glenn Miller and Harold Dickinson, "Flagwaver", "Solid As a Stonewall Jackson" with Chummy MacGregor, "Oh So Good", "Jeep Jockey Jump", "Enlisted Men's Mess", "Keep 'Em Flying", "V Hop" or "V For Victory Hop", "Passage Interdit", "Snafu Jump", "A Love Song Hasn't Been Sung" with Bill Conway and Harold Dickinson, "Are You Rusty, Gate?", "Here We Go Again", "The Spirit is Willing" and his most famous song, "A String of Pearls". So many of Gray's pieces became best-sellers that he has been described as more responsible for the band's success than Miller himself, although publicly, Gray always described the relationship as mutually beneficial.