Horatio Caine was born in 1960. He owes his first name, Horatio, to the American author Horatio Alger, whose novels were targeted on how to establish oneself in a life in disadvantaged circumstances, to fulfil the dream of wealth and success, which was influenced, loud Alger, by courage, work, determination and commitment to others. Horatio Caine has a younger brother, and was often beaten by his abusive father in his childhood and youth.

After the murder of their mother, Horatio took care of his brother, Raymond, alone. Upon completion of high school, Caine first attended the police academy and then began his work in the police service of New York. During the inquiries regarding offender Walter Resden, Caine was stabbed and seriously injured. After his recovery, he returned to New York and was transferred to Miami, where he also worked as a Homicide Detective. He was later trained as a demolitions expert, however, and joined the bomb squad.

At the beginning of the first season of CSI: Miami, the viewer sees the then Sergeant Caine, close to his promotion to lieutenant, being appointed head of the Crime Scene Investigation. Due to his persistence and his commitment, Horatio Caine (played by David Caruso) succeeds build a new laboratory on an unused CSI property, which may be seen throughout the entire series.

Caine is a specialist in the areas of arson and explosion traces. In addition, he is a very patient investigator with a photographic memory. In conversations with suspects, Lieutenant Caine is always with his narrow side turned to the respondent, and sees him from the bottom up at an angle. He also has a dry sense of humour and exerts his unobtrusive way in a thoroughly attractive effect on women. He can also be very good with children.

He is very popular as chief among the members of his team, because he has an open ear for everyone and also protective introduces his staff from case to case.

In the course of the series, Horatio gets to know the sister of his colleague, Eric Delko, and he and Marisol gradually fall in love and get married. Delko, who initially had a problem with their relationship, got used to it in the course of time. After the wedding, Marisol is murdered by a drug dealer, who then flees to South America. Together with Eric Delko Caine makes his way to avenge his murdered wife. In Rio de Janeiro, the two detectives track down the killer. In the ensuing knife fight, Horatio and his friend Eric manage to protect the other employees, but Antonio Riaz loses his life.

In addition to his wife's death, Horatio Caine had to fight with fate many times. For example, it was determined in the course of the series that his own father had killed his wife. His brother, Raymond, who is also an undercover agent working in the police service, is murdered in the course of an investigation, and it turns out a long time later that this death was faked so that Raymond could pursue further investigations undisturbed. After finding out that his brother is still alive, he helps his wife, Yelina Salas, and their son, Ray Jr., to go into hiding.

Raymond brought his brother, Horatio, in trouble in other ways too. So it turned out that Raymond had a relationship with a drug addict and out of this relationship came a young daughter. When the girl drowned, the mother turns to Horatio, who is marked by the striking resemblance to his brother immediately.

However, Raymond's wife, Yelina, is also struck by this similarity, which is why Horatio initially claimed that it was his daughter. He later cannot avoid telling Yelina the truth, because the girl is suffering from leukaemia and Horatio is out of the question as a brother. Raymond’s and Yelina’s son, Ray Jr., comes as the donor in question, so Horatio must tell Yelina the truth. Horatio's relationship with Yelina is purely friendly, and even though in love with her, he has never opened up about his feelings.

Throughout the series, Horatio Caine has been having an affair with Rachel Hunter, who is then killed after a dinner. Due to the traces found at the scene, Caine becomes a suspect in his girlfriend’s murder.

As it turns out, Horatio Caine has a son from his ex-wife, Julia, in which he fell in love at the beginning of his career as an undercover deployment officer. During his deployment he lived in Pensacola in Florida, about 670 miles away from Miami, where he met Julie. After finishing his assignment, Julia had disappeared without telling him anything about her pregnancy. Since Julia does not care for her son, Kyle grew up in various foster homes and foster families. When Kyle becomes a murder suspect, Lieutenant Caine tries to protect his son and take care of him.

Horatio Caine does rarely show emotions, but, unlike Dr. Gil Grissom in the series CSI: Crime Scene Investigation, he is always interested in personal terms to solve a crime and often shows compassion for the victims and the bereaved.

In each episode, Lieutenant Caine repeatedly plays around with his sunglasses, puts them on or off, puts them in or out of his pocket. In one of the episodes it is clear that he has received these glasses from Eric Delko given, who was not yet a part of CSI: Miami. Delko has long been looking for suitable glasses for the lieutenant and finally decided on these ones, because he was of the opinion that they would be perfect for Caine.