September of My Years was released in August 1965 by Reprise Records. The album was produced by Sonny Burke and arranged and conducted by Gordon Jenkins. Recording sessions took place at Reprise Studios in Hollywood, California, in April 1965.
The album is a concept album reflecting on middle age and the passage of time, with Sinatra turning 50 in December 1965. The lead track, 'It Was a Very Good Year', became a hit and won the Grammy Award for Best Male Vocal Performance in 1966.
The album reached number 5 on the Billboard 200 chart and was certified gold by the RIAA. It is considered one of Sinatra's most personal and mature works, noted for its orchestral arrangements and introspective lyrics.