Main •
Jung Kyung-ho as Kang Da-wit •
Park Yoon-ho as teen Da-wit • Choi Jae-yoon as young Da-wit : A former judge who becomes a
public interest lawyer. •
So Joo-yeon as Park Gi-ppeum : An activist in the labor union. His estranged father is the powerful conglomerate Chairman Jang Hyun-bae. •
Seo Hye-won as Yoo Nan-hee : Oh Gyu-jang's daughter. Her ambition is to transform O&Partners into a world-class law firm by prioritizing the law firm's growth and her own goals over justice and truth. •
Kim Kap-soo as Oh Gyu-jang : Founder of the leading law firm O&Partners, a figure of powerful lobbyist controlling political policy behind the scenes. •
Choi Dae-hoon as Woo Myung-hoon
Guest appearances • as Baek Han-byeol, the granddaughter of Baek Joong-seop, who runs a dog café. •
Lee Moon-sik as Shin Jung-suk, Chief Justice (Ep. 1, 4, 9–12) •
Kim Jung-young as Kim Sung-rye, Kang Da-wit's mother whose hand was severed due to excessive overtime in Yoo Jae-bum's father's factory and then passed away suddenly when Da-wit was a high school student (Ep. 1, 2, 5, 9) •
Yun Je-wook as Yoo Jae-bum, a conman who pretended to be Kang Da-wit's elementary school classmate in order to take revenge against Da-wit by framing him for receiving a bribe (Ep. 1, 8–10) •
Sung Dong-il as Choi Ho-jip, Chief Judge who is notorious for his prickly nature in the legal community (Ep. 2) •
Yoon Sang-jung as Ji So-yun, the rescuer of the puppy Byuli (Ep. 2) •
Lee Chun-moo as Kim Kang-hoon, a 12-year-old child on wheelchair due to
paraplegia and wants to sue God for damages (Ep. 3, 4) •
Jung Sae-byul as Jung So-min, Kang-hoon's mother who is pushed to the limits of life while raising her disabled son alone (Ep. 3, 4) •
Yoo Jae-myung as Choi Woong-san, Woongsan Group and hospital's chairman who advocates anti-abortion hospital policy due to his religious beliefs (Ep. 4) •
Choi Hee-jin as Kim Jin-oh, a visually impaired judge (Ep. 3) •
Lee Dae-yun as Kook Young-joon, the
appellate court judge (Ep. 3, 4) •
Jung Hoe-ryn as Kaya, an immigrant from Myanmar who wants a divorce due to her father-in-law's sexual assault (Ep. 5, 6) •
Sung Yu-jin as Goo Ji-won, the judge who grants Kaya's divorce case and allows her to maintain her residency status (Ep. 5, 6) •
Lee Jong-won as Jo Kang-ryul, Chief Judge who believes in South Korea being a country of freedom and justice (Ep. 6) •
Jung Ji-so as Elijah, popular singer/idol who has been continuously harassed by cyber-bullying activist Ma Young-sook and by some fans obsessed with her (Ep. 7, 8) •
Oh Min-ae as Cha Jin-hee, Elijah's domineering and manipulative mother who is the CEO of her agency 'EK Entertainment' (Ep. 7, 8) •
Jang Duk-soo as Kang Min-ha, employee at a luxury brand store taking the stand as a key witness against Cha Jin-hee (Ep. 8) •
Kim Yong-joon as Yoon Baek-man, Yoo Jae-bum's father who owned a paper factory where Kang Da-wit's mother worked (Ep. 9, 10) •
Song Young-chang as Jang Hyun-bae, a powerful conglomerate chairman who was sentenced to a heavy prison term by Kang Da-wit for habitual assaults on employees and a forced sexual assault on a domestic helper (Ep. 1, 11–12) ==Production==