The album's story concept was conceived by Joyce Bogart, Susan Munao and Donna Summer based on an idea by Al Bogatz.

Once Upon a Time is another concept album—the first "disco opera" per Robert Christgau[3]—developed by Joyce Bogart, Susan Munao and Donna Summer as a modern-day Cinderella narrative.

Throughout the album and as described in the liner notes storyline,[3] the songs tell the story of a young woman who lives in a fantasy world of make-believe in which she is seemingly trapped, but thanks to her belief in her dreams she embarks on an adventure that ends with the man she loves entering her life.

The Bay State Banner noted that Once Upon a Time "was one of the most candid portraits of fantasy and insecurity yet issued in the disco genre, and its confessions were credited to Summer's own pen.

"[11] The Globe and Mail praised "A Man Like You", writing that Summers "doesn't groan or pant out her version of sexspeak, she actually opens up and sings...