As a musical creator and performer, Mobley may be one of jazz's more underrated figures. He had a sound on the horn which he himself identified as "round," a gorgeous, centered tone filled with soul and tenderness. "The most lyrical saxophonist I've ever heard," Benny Golson said. "He sang into his horn."
Mobley's musical knowledge was highly refined, and emerged with particular clarity in his sophisticated harmonic approach. Horace Silver recalled that "He'd write some different, alternate changes, and they'd always be so inventive and so creative, so beautiful. A very musical mind, a harmonic mind." As far as his rhythmic concept went, Al Grey captured the impact of Mobley's playing as well as his writing when he noted that "All of Mobley's tunes flow so freely, you can really swing with them - I mean really swing!"
In addition, Mobley possessed organizational skills unusual in a musician who spent so much of his career as a sideman. He had a special knack for writing material for the blowing sessions of the period, often coming up with compositions in the studio on the spur of the moment. These pieces, frequently containing harmonic wrinkles that set them apart from mere rewrites of standards, were designed with the specific players on the date in mind.