My Golden Life

• Park Si-hoo as Choi Do-kyung[3]

He is the only heir to Haeseong Group and the head of Strategic Planning Team. He is a third generation chaebol who has returned from the USA after finishing his MBA. He is a gentleman with admirable physique and elegance. He takes pride in the fact that he practices Noblesse Oblige unlike other chaebols who like to power trip. When the "perpetrator" of an accident involving his car, Seo Ji-An, is later revealed to be his younger sister, 'Choi Eunseok,' his life takes a new turn.

• Shin Hye-sun as Seo Ji-An[4][5]

She is on a probationary two-year contract with the marketing team of Haeseong Group. Before her father went bankrupt 10 years ago, she used to be the original 'girl crush.' Everyone admires her competitive spirit and cheerful personality. Now she only dreams of being a full-time employee of the Haeseong Group. When that dream is shattered by a friend with wealth and connections, she hits rock bottom. Then, like a miracle, she gets a chance to reverse her life as the daughter of Haeseong Group. She chooses to take the silver spoon and live a glamorous life. But unexpected challenges are waiting for her.

• Lee Tae-hwan as Sunwoo Hyuk[6]

He is Ji-An’s high school friend. With a major in interior design, he runs a DIY furniture shopping mall. He has a cheerful and feisty personality, but he also has a cranky side and his likes and dislike are very clear. Ever since he fell in love with Ji-An at first sight in high school, he has had a crush on her. He does not realize that Ji-Soo, who has a crush on him, is Ji-An’s twin sister.

• Seo Eun-soo as Seo Ji-Soo[7]

Ji-An’s twin sister; After graduating from vocational college, she has been making a living as a part-timer for years. She is without a worry in the world. Since she loves bread so much, she gets a job at a local bakery. Without knowing the relationship between Ji-An and Sunwoo, she has a secret crush on Sunwoo. When her twin sister enters the chaebol family, she learns the secret behind her birth and becomes confused.

• Chun Ho-jin as Seo Tae-Soo, the twins' father

Tae-Soo has been the breadwinner for his family for his entire life. He previously had a successful life as a self-made businessman, but after going bankrupt some years earlier, he has been working as a day laborer but struggles with discrimination due to his older age and his wife being vocal of her shame at his plight.

• Kim Hye-Ok as Yang Mi-Jung, the twins' mother

She thought she would live as a housewife without ever having to get her hands dirty. Her pride is battered with her husband Tae-Soo’s bankruptcy. Reality makes her a pessimist and her negative attitude and constant complaining often annoy her family. She prays that her daughter Ji-An, who enters a chaebol family, does not end up like her.

• Lee Tae-sung as Seo Ji-Tae, the twins' older brother

Ji-tae is the eldest of Tae-soo's four children. Having graduated from university abroad, he is the envy of his younger siblings as he has a full-time job and a steady girlfriend. Burdened with having to help pay off his father's debt, he hides his own struggles from his family and will do anything for them, including sacrificing his own happiness.

• Shin Hyun-soo as Seo Ji-Ho, the twins' younger brother

Ji-ho is the youngest of Tae-soo's four children. At the beginning of the series he was a high school student preparing for the college entrance exam and worked part-time to save up for his college tuition. Cheerful and happy-go-lucky by nature, he is doted on by his family and is fiercely protective of his siblings.

• Jeon No-min as Choi Jae-Sung, Do-Kyung’s father. He and Myung-hee were university sweethearts and he married her even after finding out about her background as a chaebol heiress. Although he works for his in-laws' company, he feels suffocated and despises the cold mannerisms and lack of personal relationships between his in-laws.
• Na Young-hee as Noh Myung-Hee, Do-Kyung’s mother and elder daughter of Noh Yang-ho. She is portrayed in the story unsympathetically as a rather self-centered lady, possibly because of her upbringing and manipulation of her over-bearing father. She tends to be uncaring towards others, especially people of inferior wealth and influence in comparison with her.
• Lee Da-in as Choi Seo-Hyun, Do-Kyung’s younger sister. Although appearing to be a typical "golden child", she hides a more rebellious side of her from her brother and parents and wishes to explore the world outside of her family's bubble of wealthy friends and connections. She feels left out when her parents, especially the mother, fuss so much over the return of her missing sister.

• Kim Byung-Ki as Noh Yang-ho, the family patriarch and former chairman of Haesung Group
• Jeon Soo-Kyung as Noh Jin-Hee, Noh Yang-ho's younger daughter
• Yoo Ha-Bok as Jung Myung-soo, Noh Jin-Hee’s husband
• Seo Kyung-Hwa as Min Deul-lae, Choi family's household manager
• Wi Ha-Joon as Ryu Jae-shin, Choi Seo-Hyun’s former driver