Yussel Rabinovitch is a young, fifth-generation Jewish cantor performing at the synagogue of his imperious father. Yussel is married to his childhood friend Rivka and has settled down to a life of religious devotion to the teaching of his faith.
But on the side, he writes songs for a black singing group, and when a member of the quartet is arrested, Yussel covers for him at one of their gigs by wearing blackface. The nightclub engagement is a success, but one of the patrons at the nightclub notices that Yussel’s hands are white and becomes outspoken. A fight ensues, and the band is arrested. Yussel’s father comes to the jail to bail them out and finds out that there is not a Yussel Rabinovitch there but a Jess Robin. His father questions him about this later, and Yussel tells him it is a professional stage name he uses when performing. His father tells him that his singing voice was to be used for God’s purposes, not his own.
Bubba, a member of the Four Brothers singing group, is Yussel’s best friend, although he knows him as Jess; Bubba informs him that the band has got a gig in Los Angeles performing back-up vocals for Keith Lennox,a successful singer. Shortly after Bubba leaves, Yussel begins composing a song that will eventually become “Love on the Rocks”. His wife Rivka notices him writing the song in his free time and senses that Yussel yearns for a bigger stage for his voice, but her values keep her grounded to the home life they have built.
Bubba calls Jess from Los Angeles and informs him that Lennox really loved “Love on the Rocks” and wants to record it, but they need Jess to come for two weeks to oversee the recording session. Jess finally sees this as the opportunity he has been waiting, but his wife and his father are opposed to his going. But later at his father’s 25th anniversary party as shul cantor, his father relents and tearfully lets him go.
When Jess arrives in L.A., he is picked up by music agent Molly Bell. She takes him to the studio where Lennox is recording, and Jess is shocked to find that his ballad is now being recorded as a hard rock song. During a break in recording, Jess asks the producer and Lennox if he can perform the song as a ballad, as he intended, so Lennox can get an idea of the framing of the song. They allow him to do it, and while recording the song, Molly decides that Jess’s performance is the way the song should be done. However, Lennox is not convinced and fires the group.
Later, Molly gets a tip from a friend as to where Eddie Gibbs, a booking agent, is having lunch. She gets into his car, uninvited, and has him listen to Jess’s recording of “Love on the Rocks”. When Eddie asks her who it is, Molly tells him that it is the new opening act for Zane Gray’s new television special. Gibbs is not amused and says he can’t book anyone from just a tape recording. However, she manages to get Eddie to visit a club where Jess has managed to get a gig playing, thanks to Bubba, who is working there as a waiter. Eddie comes in and watches his performing “Amazed and Confused” and then leaves. Jess thinks he has blown it, but Molly tells him “he hates loud music…you he loved…you open for Zane Gray.”
Meanwhile, back in New York, Cantor Rabinovich confronts Rivka about Jess going to California, and reminds her that her place is by her husband’s side, and if she goes to California, maybe she can bring him home. She relents and goes.
On Jess’s opening night, as he performs the songs “Summer Love” and “Hey Louise”, Rivka shows up and meets Molly, and tries to tell her that their Jewish values are such that Jess cannot possibly stay. The audience gives Jess a standing ovation, and he heads backstage and is reunited with Rivka. At the after party, Jess is met by an enthusiastic crowd and is given a recording contract. Despite Jess’ asking her to stay, Rivka says she wants something different. Realizing she has lost him, she leaves before Jess can catch her.
Days later, Jess meets with Molly by the pier and confesses his love for her, telling her that he and Rivka have split. As time passes, the two grow closer to each other, and Jess’ career continues steadily. His father visits him and attempts to persuade him to come home, but Jess refuses, insisting that he’s making a name for himself with his music career. Jess reveals that he and Rivka are divorcing, which devastates his father. To make matters worse, Molly suddenly arrives home. Jess tries to explain the matter to his father, but to no avail, as he angrily disowns his son and leaves in tears.
Still broken by the incident, Jess struggles at his recording sessions, taking out his anger on his band mates, until he finally storms out and drives away aimlessly. When his car runs out of gas on the highway, he hitchhikes far away for a few weeks, eventually singing at a country bar. He returns home to Molly when Bubba tracks him down and tells him that she has given birth to a son. Molly once again meets Eddie Gibbs in his car and persuades him to let Jess perform on Zane Gray’s television special.
At rehearsal, the day before Yom Kippur, Leo shows up and tells Jess that his father is in the hospital with high blood pressure and won’t be able to sing Kol Nidre at the synagogue. Jess is initially reluctant to go to his father, vowing that he is dead to him, but Molly insists that he go to him or else she’ll feel guilty about it. Jess ultimately agrees and returns to sing at the synagogue. He tries to make amends with his father, but he refuses to speak to Jess until Jess tells him that he now has a grandson, at which point they finally reconcile.
The film ends with Jess performing “America”, with his father and Molly in attendance.