There's a party at Delray's, an underground African-American Rock and Roll bar in 1950's Memphis. Huey Calhoun, a white man, arrives on the scene. The regulars begin to leave, but Huey convinces them to stay, claiming he is there for the music.
Later, Huey is about to be fired from his job as a stock boy at a local department store, but he makes a deal with the owner - if he can sell 5 records by playing them over the speakers, he can have a sales job. Huey plays a Rock and Roll hit. He sells 29 records in a matter of minutes, but the store owner fires him anyway, incensed at the type of music being played.
Huey returns to Delray's club, and begins flirting with Felicia and promises to get her on the radio. Huey then proceeds to apply for DJ jobs at various local white radio stations. One of the owners, Mr. Simmons, invites him in, saying he'll show him what a 'real' DJ looks like. Huey hijacks the mic, and plays another African-American rock song. Mr. Simmons is about to have Huey thrown out, but then dozens of teenagers start calling in demanding more of Huey and his music. Mr. Simmons agrees to give him a two-week trial, and if he's successful he'll get hired full time. After a few days Huey is told to read an advertisement for beer, but he is illiterate. Huey asks Bobby, a friend of Delray's with a janitor position, to tell him what it says. He forgets the exact words almost immediately and begins to improvise, ending with the phrase "Hockadoo!".
Huey's station gains immediate popularity, as does his new catch phrase, even though no one understands what it means. Meanwhile, Delray has saved enough money to put Felicia's voice on the record, and she travels to Huey's house to tell him this. Huey's prejudiced mother, however, breaks the record, which leaves Felicia heartbroken, but Huey tells her to come down to the radio station anyway.
Felicia and Huey's relationship begins to grow, and Delray is becoming more and more infuriated with Huey. He warns him of the danger of what he is doing, threatening to harm Huey if anything happens to Felicia . Two years later Huey proposes to Felicia on the way to a party at Delray's. She says no because of laws and prejudice, but admits that without those obstacles she would accept. As the two share a kiss, a gang of white men pass by, spotting this. They hold Huey down as they beat Felicia with a bat. Huey manages to carry her into the club, crying out for help.
Time has passed, and Huey is about to open his new TV show, a rock and roll variety show featuring all African American dancers. Felicia is supposed to be his first guest, but she backs out at the last minute, fearing that people will think her and Huey to be in a relationship. Huey informs Bobby that he will fill in, and brings the house down. Felicia tells Huey that if they went to New York they wouldn't have to sneak around all the time, but Huey insists that they are happy the way they are and don't need to leave.
She has been discovered by a talent agency in New York, as has Huey's TV show. The agency wants them both to come up to New York, although Huey has to compete with a local Philadelphia DJ, Dick Clark for the national show. Huey is told he has won the TV position, if he agrees not to use African American dancers. Huey refuses, and proceeds to strip out of his suit on the air. Felicia tells Huey that she plans to go anyway, as it is her dream. In a desperate attempt to keep her, he kisses her on the air, and says he loves her.
The feed is cut, and Huey is fired on the grounds that no one would watch his show if they knew about him and Felicia. Now unemployed, Huey leaves the station and ponders his relationship with Memphis, realizing he couldn't leave for any reason.
Four years later, Huey is a DJ on an obviously low budget and low rated station. Felicia walks in, about to start a national tour. She tells Huey that she is engaged to a man named Bill, but that she wants him to join her on stage one last time. He refuses, afraid that no one will remember him. She begins her performance, and halfway through the song Huey walks on stage, and finishes the song with her to thunderous applause. He then proclaims "The name is Huey Calhoun. Goodnight and HOCKADOO!"