Midway through the second act of the play, after the principals Curly and Laurey are married, Curly begins to sing the song and is soon joined by the entire cast as a chorus. The lyric, which briefly depicts the Midwestern twang phonetically, describes the landscape and prairie weather in positive language. It further emphasizes the wholesome aspects of rural life, and the steadfast dedication of the region's inhabitants, against the overtly stated formal backdrop of the territory's impending admission to the Union in 1907.
Hammerstein's lyric is also notable and memorable for its trochaic re-iteration of its title as a chant, and the final iambic eight-letter spelling of the title as a play on the colloquial English word "Okay". Orchestrator Robert Russell Bennett's massive 8-part chorale near the end of the song, extends it to include a spelling of the name, ending with an epic ritardando leading into one last iteration of "Oklahoma!"
The state of Oklahoma officially adopted the song as its state song in 1953. It is the only official state song from a Broadway musical. State Representative George Nigh, who later served as the state's Governor, was the principal author of the legislation designating the state song.