Adam Lemp (Rains) is a flutist and music professor with the titular four daughters, Ann, Kay, Thea, and Emma. Kay is a singer while the other daughters play musical instruments, and the family entertains themselves by playing songs together at home. Their placid existence is disturbed by rakish, charming composer Felix Dietz, and Felix's buddy, the even more rakish and more charming pianist Mickey Borden (Garfield). Many romatic comlications ensue.
Four Daughters was the film debut of Garfield, who went on to a very successful career as a leading man. Three of the sisters were played by Real Life sisters: Priscilla Lane (the big star, as Ann), Lola Lane (Thea), and Rosemary Lane (Kay). The fourth sister, Emma, was played by Gale Page.
- Bad "Bad Acting": The obviously rehearsed, badly delivered little spiel about Thea that Ann delivers to Ben.
- Bookends: In the last scene, Mr. Lemp and the four Lemp daughters are having a concert, just as they were in the first scene. Ann is bothered by creaking as she plays the violin, just as she was in the first scene. It's Felix swinging on the gate, again.Felix: Say, this is where we came in.
- Driven to Suicide: Mickey, ridden with guilt over not providing for Ann and sensing on some level that she has regrets about choosing him over Felix, crashes his car on purpose, and dies.
- Everybody Smokes: Your husband is in the hospital, dying of injuries suffered in a car crash. What do you do? Why, you offer him a cigarette, of course. The doctor says okey dokey, but Mickey dies just as Ann is getting his smoke lighted up.
- Gold Digger: Thea is quite up-front about marrying Ben Crowley, the richest man in town, for his money. She doesn't even fake affection for him, although she later expresses shame for not even trying to be a good wife.
- I Want My Beloved to Be Happy: Done twice. First, when Ann realizes Emma is in love with Felix, she leaves Felix at the altar to marry Mickey in order to clear the way for Emma. Later, Mickey is Driven to Suicide when he realizes Ann and Felix still have feelings for each other.
- The Klutz: Ernest, Emma's beau, is often stumbling into or tripping over things.
- Last-Name Basis: Felix and Ann insist on calling each other Dietz and Lemp.
- Love Dodecahedron: Let's see. Felix is in love with Ann. All three of the other Lemp sisters look disappointed when Felix and Ann are getting engaged. Mickey is also in love with Ann. Emma loves Felix, crying when after Felix and Ann announce their engagement. Emma later falls in love with Ernest, who's been after her all along. Thea is clearly sweet on Felix, even though she's marrying Ben. So, yes, it counts.
- Maiden Aunt: Little is told of Aunt Emma's back story, and she seems content to be a quasi-maternal figure for the Lemp girls. She calls herself a spinster.
- Meet Cute: Ann (and the other daughters) meets Felix when he swings on their gate, making a squeaking sound that interrupts her violin playing.
- Missing Mom: Not a hint of the status of Mrs. Lemp.
- Recitation Handclasp: Kay does this when singing a song on a national radio broadcast.
- Starving Artist: Mickey is a talented musician but is perpetually broke. His luck doesn't change after he and Ann get married; she has to pawn her stuff to buy food.
- Swing Low, Sweet Harriet: Ann swings on a swing at a family picnic. More in an innocent free-spirit manner than some of the more fanservice-y instances of this trope.