An American composer. He was a precocious talent, composing his first opera at age 13 and entering Harvard University at 14. He also studied in the music department at Yale University. He studied privately with Ernest Bloch and served as Bloch's assistant at the Cleveland Institute of Music. He received numerous scholarships, including those from the Guggenheim Foundation, the American Academy in Rome, and Carnegie. He also had teaching experience at the music departments of Smith College, Princeton University, and the University of California.

His compositional style, while showing some influence from Bloch, possessed an even greater rigor. Perhaps for this reason, Sessions's works are considered more difficult to perform than those of other composers and have been criticized for their lack of accessibility. However, from another perspective, he can be regarded as an intellectual composer. Works that include piano in their instrumentation include the Piano Concerto (1956), Piano Sonata No. 1 (1930), and Piano Sonata No. 2 (1946).