Cinderella's Stepsister

Song Eun-jo/Goo Eun-jo - A cynical and shy young woman, Eun-jo is good at hiding her emotions and does not get attached to people easily. She is skeptical of her stepfather's kindness; however, she later realizes that it is genuine and this realization begins to break her hard exterior. Eun-jo is in love with Ki-hoon, and is hurt when he leaves, leading her to be cold and reject him when he returns 8 years later. She later mourns her stepfather's death.

Hong Ki-jung, Ki-hoon's manipulative and calculating older half-brother, who does not even acknowledge Ki-hoon as his brother.

Chairman Hong

Goo Dae-sung - Hyo-sun's father and Eun-jo's stepfather. Dae-sung is kindhearted, genuine, and loving. His character and goodness causes changes in everyone around him for the better.

Goo Hyo-sun - A gentle and brilliant girl who has been treated like a princess her entire life. However, she is lonely and becomes excited when she learns that she'll be getting a new mother and sister. When her new family members are different from what she expected, it takes a toll on her. Hyo-sun is slightly spoiled and becomes jealous of her new stepsister.

Hong Ki-hoon - Gentle, handsome, and kind, Ki-hoon sees much of himself in Eun-jo. However, when his difficult and broken family situation causes him to leave the winery, he disappears, leaving Eun-jo a letter that she never receives. Ki-hoon returns 8 years later and appears to be a spy for his evil step-family's company, but not everything is as it seems.

Song Kang-sook - Eun-jo's mother. Knows how to get what she wants, and marries Go Dae-sung for his wealth. Though initially an evil stepmother who fakes affection for her new family, Kang-sook does love her daughter Eun-jo in her own way and begins to change as a result of Dae-sung's love for her.