Sang Min Soo is a snakehead facilitator originally from Korea who specializes in human trafficking.
In Pilot, Sang Min is first seen as a human trafficker with ties to Victor Hesse. He first meets the Five-0 team when Kono goes undercover as a women looking to move her family to America. She gets into trouble when Sang Min send her photo to a cop to see if anyone recognizes her as a cop. When she is recognized his men go to shoot when she attacks both of them and then McGarrett and the rest of the team move in to help. They capture Sang Min and release other families he had brought over that were in a shipping container. 
In Mana'o, Danny visits Sang Min in prison when his old partner was murdered and wanted to know who his mole was. He later identified Detective Kaleo as his mole. In exchange for identifying his mole, Danny takes him to visit his family, but he declines, claiming he caused them enough pain.
In Hana 'a'a Makehewa, upon discovering Hesse is alive, Steve and Danny release Sang Min to get him to help find Hesse. Finding him in a club, they cuff Sang Min to the wheel of Danny's car, but he easily escapes with a paper clip to unlock the cuff, later helping Hesse escape before going on the run himself.
In Ua Hiki Mai Kapalena Pau (episode), while searching for Wo Fat, the Five-0 team discover Sang Min was in the house Wo Fat was supposedly hiding in and manages to evade police. He later arrives at their headquarters, surrendering because he tried to make things right and warns Steve that Wo Fat will be after him next.
In Pu'olo (episode), upon hearing Wo Fat killed Hesse and Jameson, he started a fire to get himself into solitary for protection. He is soon temporarily released to help the Five-0 team apprehend a suspect and was later transferred to a mainland prison.
In Kapu, he is transferred from the mainland and later escaped to see his family, but upon seeing them with another man, he gives himself up and is granted his request to be close to his son.
In Olelo Ho'Opa'I Make, when Chin was drugged and thrown into prison, Sang Min saves him from Kaleo and punches him for hitting him with an ashtray the first time they met. During the riot, Sang Min betrays Chin and uses the distraction to disguise himself as a guard, as well as cutting his hair, to escape from prison.
In Ina Paha (episode), the team get Sang Min, who was arrested after finding him hiding in a bush with poison ivy on him, and hair grown back, to help again and as they were arresting a suspect, Sang Min claims he is Five-0, but Grover tells him he is just a snitch. Later when Steve was kidnapped by Wo Fat, they bring him in to assist them.
In Ka Pohaku Kihi Pa'a, Sang Min is released from prison, only to come across a murder and accidentally incriminates himself by handling the murder weapon and shooting at the killer. Steve, who knows he is innocent, hires Odell Martin as his lawyer and in exchange he cuts Sang Min's hair. After being found not guilty, Sang Min was now wearing glasses and Odell keeps his promise to cut his hair, despite Sang Min's objections.
In E mālama pono, when McGarrett comes home following a lecture, he comes across some blood leading into his kitchen, only to discover Sang Min, hair once again grown back, wounded from a gunshot, who sarcastically apologises for his mess. Since he was still a fugitive despite being acquitted, Steve brings in Noelani Cunha to patch him up. Later at the end of the episode, he crashes Grover's dinner roll on purpose, still unhappy about what he said about not being their guy. As Danny talks about his plan to open a restaurant, he tells Sang Min that he is not welcome due to his mullet.
He is cheeky, full of himself and obnoxious but is a funny character. He can be cunning, as seen when he escapes from Danny Williams's car. He is also flirty when he sees a pretty girl especially Officer Kono Kalakaua. He often hits on her, calling her "spicy", when she is seen interrogating him it is his special nickname for her.
Sang Min, when out of prison, usually has his black hair slicked back. He regularly wore it long until his lawyer, Odell Martin, cut his ponytail, but later grew it back. When working with the Five-0 task force, Sang Min usually wears all black, or occasionally white t-shirt with black slacks. Sang Min has myopia caused by blunt ocular trauma (nearsightedness due to being hit in the head in a way that affects his eyes). He resisted wearing glasses for many years, but at the end of Season 6 and after he could occasionally be seen wearing black acetate frames in a squared aviator style.
We are unclear if he has any fighting skills such as martial arts, but because he is involved with human trafficking we know he must be able to fight but he never goes into a meeting alone, as seen in the first season of Hawaii Five-0, and in season 2 episode 10. In season 3 episode 13, he was able to take down two prisoners and escape from prison.
- He is the first criminal that Five-0 catches.
- He is protective of his mullet, and is often teased because of it.
- His mullet was cut twice in the series.
- He calls Kono 'Spicy'.
- In E mālama pono, he reveals he has gone vegan.