Raymond was an Army brat born in Seoul, South Korea, and consequently calls the sport of soccer football. His father, a decorated soldier and a veteran of the Korean War, was a violent man, often involved in brawls off the battlefield; as a result, Langston's childhood was a painful one.
Raymond eventually obtained a medical degree and became a pathologist at a hospital. A co-worker at his hospital was an Angel of Death, murdering 27 patients. While Langston saw the evidence, he was never able to put it together.
Afterward, Langston became a professor at West Las Vegas University, but continued to do pro bono work as a surgeon. It was in this capacity that he came into contact with the CSI team, as they were investigating a series of murders attributed to serial killer Nate Haskell, who Langston interviewed for the course. After the case's conclusion, Grissom encouraged Langston to join the Las Vegas Crime Lab as a Level 1 investigator.
In season 9, Langston began his first day on the job. His first day was troubling for him as he overdusted a print and ruined it, dropped a burned body and tearing its shift then getting his necktie stuck in the victim's blood, causing it to become evidence, and drawing Riley Adams' criticism when he reprimands a man who strikes his son.
He also received a cold welcome from David Hodges, who was still unhappy about Gil Grissom's departure, but who warms up to Langston after the latter demonstrates a cornmeal bomb. Nevertheless, the team accepts him as one of their own, inviting him to join them at a diner.
n later episodes, it is revealed that Langston has a number of interests, including blues music and quickly befriended the like-minded Doc Al Robbins.
It is revealed in one episode that Langston knows some Mandarin Chinese. He is the only member of the team who rides a motorcycle to work.
Langston, despite his calm demeanor, occasionally takes cases personally. In his first case, he reprimanded a father for shouting at his son while the team was searching the boy's room, earning a reprimand from Riley about keeping an emotional distance. He was forced to kill a suspect in self-defense in the Season 9 finale, "All In"; his lack of guilt over the event worries him. It was the first time he had taken a life in the line of duty.
By the tenth season premiere episode, Langston has taken numerous courses (going so far as to max out the hours the lab will pay for and paying out of his own pocket) and has since been promoted to CSI Level 2. He said no to giving his DNA to the crime lab to clear him from the investigation; the reason why is later speculated on by Wendy Simms and David Hodges, though the two draw no concrete conclusions.
Serial killer Nate Haskell first appears in the Season 9 episode "19 Down", the first part of the final episode of Gil Grissom, the former Supervisor of the crime lab. Langston was a professor of forensics and taught a class in college. Grissom comes to one of his classes, which is when Haskell is mentioned. After Langston became a CSI following Grissom's retirement, Haskell emerges again when he calls Langston in the first part of the Season 10 finale "Doctor Who."
At the conclusion of Season 10 ("Meat Jekyll"), Langston is stabbed by Haskell in the closing minutes of the second part of the finale and collapses to the ground, bleeding.
In the eleventh season premiere, Ray survives the attack but has lost one of his kidneys as a result and regularly needs a cane to help him although in later episodes, he seems to have fully capable of walking without it.
Later in the episode "Bump and Grind," Langston receives a letter from Haskell, where he finds a kidney bean and note that says, "Just thinking about you, XO, Nate". In the end of the episode, he looks at the scars that Haskell gave him and Sara Sidle walks in. He tells her about the letter that Haskell sent him, and Sara tells him to not let Haskell get in his way.
Later in the episode "Targets of Obsession", Langston goes to court to testify against Haskell. During the trial, Haskell contends that he is a victim of his own circumstances. As a child, he was abused by his alcoholic father, and he is also a carrier of the MAO-A gene, which has been shown to predispose an individual to violent behavior. When Langston takes the stand, Haskell forces him to recount in full detail the attack at the crime lab. At first, it appears that the jury has been swayed by Haskell's testimony; however, near the close of the case, Langston returns to the stand to rebuke Haskell's MAO-A defense. When Haskell questions Langston's ability to testify on the matter, Langston reveals that he is personally equipped to discuss the influence of the MAO-A gene on a person's behavior. Like Haskell, Langston reveals, he too was abused by an alcoholic father and has the MAO-A gene. The fact that Langston has avoided becoming a criminal himself and instead takes pleasure in seeing criminals being brought to justice proves for the court that neither abuse nor the MAO-A gene can determine a person's behavior, and Haskell is found guilty.
Haskell sends a signal to his fiancée, which Langston notices while the verdict was being read. As Langston was leaving to go home after his success in court, he sees the group of women that tried to free Haskell through his defenses and becomes suspicious when he doesn't see Haskell's fiancée nor a certain other woman. He remembers the signal sent and quickly returns to the prison where Haskell was being held, and finds that there was another inmate wearing Nate Haskell's prison band. It is later shown that Haskell's fiancée helped him escape by killing the other inmates, the other prison guards, and the woman that helped her.
In the episode "Unleashed," Ray reveals to Lady Heather, that when he was applying for medical school, he was asked why he wanted to be a doctor. He responded with as long as he was helping people, he was not hurting them. Lady Heather remarks that his ugly side will be the one to catch Haskell.
In the episode "Father of the Bride," Ray and the team receive a video of Haskell. It showed his fiancée, Vivian, who helped him escape, and it appeared to be a ransom video. In the Season 11 finale, Langston snaps after Haskell hints that he (Haskell) sexually assaulted Gloria. Langston beats him multiple times, using his medical knowledge to inflict as much damage as possible to Haskell. He damages Haskell's kidney in retaliation, and breaks his knee. After a series of beatings, Ray throws Haskell over a railing killing him. Catherine sent in the report to Internal Affairs saying the evidence supports that he acted in self-defense. At the end of the episode, Internal Affairs interviews him, and asks if he killed Haskell in self-defense or murdered him. The episode abruptly ends.
In the Season 12 premiere, "73 Seconds", Brass and Doc Robbins mention that Ray is back in Baltimore with Gloria. Though Ray was not formally charged by IA, he was pressured into leaving the team, and in addition, almost all of the CSIs involved were affected in some way; Nick Stokes and Catherine Willows were demoted because of the team's attempt to shield Ray and for not bringing Ray into line during his attempt to find Haskell. - (Info courtesy of wikipedia.)
When Langston first joined, he was warmly received by the team and has a good working relationship with them. When it comes to analyzing evidence and the science, he sometimes acts as a mentor to the likes of Nick (who first gives him the title "Doctor Ray") and Greg, telling them the little known or weird facts. Hodges, who initially seemed to dislike him, eventually warmed up to his new colleague. He notably developed a friendship with Doc Robbins and the two are often seen in the morgue exchanging banter over the corpse they are examining.
Laurence Fishburne made guest appearances as Dr. Raymond Langston in CSI: Miami and CSI: NY in the tenth season of CSI, appearing in episodes aired the week of November 9, 2009. This gives him the distinction of being one of the two actors in the main cast of one CSI program to appear in the same role on all three, the first being David Caruso as Lt. Horatio Caine. However, Langston is the only character who traveled to all three locations and worked fully with all three labs.