Don Lockwood
Don is a much-loved film star of the silent movie era, who came into this position rather accidentally when he was working as a stuntman. Don is disillusioned by the shallowness of fame, as his on-screen love interest, Lina Lamont bores and annoys him. Kathy Selden's forthrightness and down-to-earth confidence attract him right away, and she helps him see more possibilities for himself and his career. He is a generous man who is not afraid to share his fame and billing with his dear friend, Cosmo, and his lover, Kathy. Don is depicted as wholesome, kindhearted, ambitious, witty, and optimistic. He is also an exceedingly talented song-and-dance man, never shirking an opportunity to tap dance. Life is a romantic adventure for Don, who sees the world through rose-colored glasses, is always looking for the opportunity to imbue a moment with movie magic, and is barely fazed by getting caught in the rain.
Lina Lamont
Lina is Don's co-star and alleged love interest. She is beautiful, but her personality is off-putting, ditzy, crass, and selfish. While the public imagines her to be a refined lady, she is anything but, and her image is maintained only by the mystery of silent films. Possessive, territorial, and easily jealous, Lina has convinced herself that the contrived romance between her and Don is actually real. Power hungry and narcissistic, Lina wants all the fame and glory for herself, and is unwilling to admit her weaknesses as a performer. Not only is Lina determined to hold onto her fame, but also to prevent Kathy from achieving fame herself. While Lina is an antagonistic force in the film, she is also a major comic presence as well, and her struggle to become a refined and silver-voiced actress is one of the funniest tensions in the film.
Kathy Selden
Kathy is a young aspiring stage actress who looks down on silent film—a form she deems "undignified," because the actors do not use their voices. When Don jumps into her car to get away from his rabid fans, she downplays her knowledge of him and insults his shallow profession. She is embarrassed, however, when Don learns the truth that she is a member of a chorus line, and a contract player with the studio. Kathy is very talented and gets a lucky break when the studio decides to hire her for their talking pictures. Ambitious, hard-working, thoughtful, and plucky, Kathy is the pure-hearted heroine and companion that Lina is not. Additionally, her speaking voice is pleasant and her singing voice superb, which makes her the perfect person to dub Lina's vocals. She is not a resentful person and takes her role as an uncredited player in the movie gracefully. Kathy is rewarded for her talent and her humility with the adoration of audiences when they learn that she dubbed Lina's vocals in The Dancing Cavalier. They come to love her almost as much as Don does.
R. F. Simpson
R.F. Simpson is the producer behind all of Lockwood and Lamont's films. He is an affable man who trusts Lockwood and Cosmo a great deal, but must make the difficult decisions based on business and sales. The task of making the studio's first talking picture proves to be a huge challenge. In fact the previews are so terribly received that Simpson is willing to take whatever advice he can get to make a successful feature. A talented businessman and a good listener, Simpson is willing to hold true to his principles, but also to take much-needed advice from his collaborators. He is fair and upright and wants to give Kathy the credit she deserves, even if Lina does not want it to be revealed that her voice is being dubbed.
Cosmo Brown
Don Lockwood's best friend since childhood, Cosmo is an accomplished musician and a consummate jokester. He always shows up to lend some much needed comic relief to any event. His song "Make 'Em Laugh" is meant to cheer Don up when he is down in the dumps; in it, Cosmo resorts to non-stop slapstick, impressive dancing, and impeccable comic timing. Cosmo loves to make light of a situation, and sometimes teases others in order to conjure some levity. He is a loyal friend to Don, and it is his idea to turn The Duelling Cavalier into a musical. He also comes up with the idea for how to make the film both a modern movie and a period piece. Cosmo is an ingenious, fun-loving, and silly friend, and a true creative.
Roscoe Dexter
The hot-headed and impatient director of The Duelling Cavalier and many Lockwood and Lamont pictures. While he puts on the appearance of patience and civility with the actors, his extreme anger is always bubbling up and overwhelming him. His artistic vision is often thwarted by Lina's clumsiness with microphones and her imperviousness to direction.
Zelda Zanders
Lina's friend and another silent film actress. She is shown arriving at the premiere of The Royal Rascal at the start of the film, reported to be married to a much older man. She reveals Kathy and Lockwood's romance to Lina, who promptly confronts them for going behind her back.
Dora
A reporter covering the premiere.
Flapper in "Broadway Melody"
Lockwood's dance partner in the dream sequence, "Broadway Melody"
Olga Mara
Another silent film starlet who attends the premiere for The Royal Rascal.