Oscar Greeley Clendenning Hammerstein II (July 12, 1895 – August 23, 1960) was an American librettist, theatrical producer, and (usually uncredited) theatre director of musicals for almost forty years. Hammerstein won eight Tony Awards and two Academy Awards for Best Original Song. Many of his songs are standard repertoire for singers and jazz musicians. He co-wrote 850 songs. Hammerstein was the lyricist and playwright in his partnerships; his collaborators wrote the music. Hammerstein collaborated with composers Jerome Kern, Vincent Youmans, Rudolf Friml and Sigmund Romberg; but his most famous collaboration, by far, was with Richard Rodgers.
Hammerstein was born Oscar Greeley Clendenning Hammerstein in New York City, the son of Alice (née Nimmo) and William Hammerstein. His grandfather was German-born Jewish theater impresario Oscar Hammerstein I, and his mother was the daughter of Scottish and English parents. Hammerstein was raised an Episcopalian.
Although Hammerstein's father managed the Victoria Theatre for his father and was a producer of vaudeville shows (he is generally credited with inventing the "pie-in-the-face" routine), he was opposed to his son's desire to participate in the arts. Hammerstein attended Columbia University (1912–16) and studied at Columbia Law School until 1917. It was not until his father's death on June 10, 1914, that he participated in his first play with the Varsity Show, entitled On Your Way. Throughout the rest of his college career, Hammerstein wrote and performed in several Varsity Shows.