Dr. John Truman Carter III called simply "Carter" by most other characters, was introduced in the pilot episode, and, without interruption, was the only main character to have stayed with the show from the beginning of the series up to the 2004/2005 season, for a total of eleven consecutive seasons. John Carter was born on June 4, 1970. He comes from a very wealthy family. His father was once estimated to be worth US$178 million, although in later seasons there are hints that this is only the tip of the iceberg. Carters career choice of medicine is contrary to his familys wishes. Something that would have better equipped him for participating in the family business (and their behemoth of a charitable foundation) would have been preferable. Nevertheless, his education is paid for in full. Carter comes to County General as a third year medical student. As a medical student, Carter is characterized as not always being the most gifted physician, but he is very dedicated and compassionate to his patients. He is initially interested in surgery -- even completing the first year of his surgical residency -- and is mentored by the surgeon Dr. Peter Benton. However, after a rotation in the emergency room, he decides to change his specialty to emergency medicine, to Benton's dismay. In order for Carter to change from his surgical residency to an emergency medicine residency, he agrees to work for free for his first year, since County General had no more funding for an additional spot.As a resident his confidence grows, and he often does whatever is in his power (or, sometimes, things outside of his power, much to the annoyance of his superiors) to help patients. During Season 6 (in his first major season-long story arc) Carter is stabbed in the back by a schizophrenic patient. As a result of Carter's chronic battle with pain, survivor guilt and resistance to getting help, he eventually develops a narcotic addiction. He begins to make a series of errors on the job. After Abby Lockhart catches him shooting up fentanyl, Dr. Weaver demands he go to an inpatient rehab center for medical doctors in Atlanta or be fired. Although initially opposed to going, he is taken by Dr. Benton. Upon returning from rehab, Carter makes peace with his recovering heroin-addict cousin, Chase, and apologizes for his long absence. During Season 9, Carter dates Abby after they were quarantined in the ER for three weeks because of the outbreak of monkey pox. They have long been attracted to each other, and their romantic relationship is the natural next step. However, Abby's brother Eric is diagnosed with bipolar disorder (like their mother) and his behavior becomes erratic. He then disappears. Meanwhile, the health of Carter's grandmother, Millicent, continues to decline, and Carter's mother has difficulty accepting her divorce from Carter's father. Worse, Abby and Carter continue to disagree over whether or not Abby (a recovering alcoholic) should be drinking at all, even moderately. These personal issues come to a head when Abby's brother reappears the same day Carter's grandmother dies. Carter is broken by his grief, yet Abby feels it is her duty to go and get her destitute brother, essentially leaving Carter alone to grieve. When the uninvited Eric behaves inappropriately at Millicent's funeral, it marks the beginning of the end of Carter and Abby's relationship. About a month later, Carter cannot shake his grief or his troubles with Abby, and agrees to go to the Congo (without Abby's consent) to join Luka and the Doctors Without Borders program. While there, he almost gets killed by guerrilla soldiers. He returns after two weeks. When Dr. Kovac is reported killed in Africa, Carter goes to retrieve his body at the beginning of Season 10. To his surprise, he finds Kovac - still alive. He arranges for Kovac to be sent home, during which he gives Kovac a letter for Abby, which is a "Dear John letter" that ends their relationship. Around this time, Wyle had his first child, and requested to have three months off from the show in order to enjoy his infant son. Producers complied with this request. To deal with this absence, Carter remains in Africa for several months. He primarily works in Kem's AIDS clinic. They initially differ on approaches to treatment, but come to respect and love each other. During Season 11, Carter starts building an HIV/AIDS clinic adjacent to County General, with full funding by his family's charity foundation. It will be named after his stillborn son - The Joshua Carter Center.Afterwards, he goes to Paris, where Kem is visiting her mother, who has fallen ill. After a very awkward reunion, their relationship begins to grow again, and Carter offers to go to Africa with Kem and start all over. She doesn't answer right away, but later accepts the offer. Dr. Carter goes back to Chicago to finish out his work with County General, and, after saying goodbye to his friends, goes to Africa to be with Kem.
Carter in Darfur
On Season 12, Carter appears in a four episode arc, working with a fellow doctor in Darfur, Sudan, where he is joined by Dr. Pratt and Debbie (Mary McCormack). Pratt informs him of Abby's pregnancy and he appears surprised. Although he and Kem have married, there is some indication that his relationship with Kem isn't working
Carter returns in the Season 15 episode, "The Beginning Of the End," when he returns to the ER at County General after being in Africa. He explains to Cate Banfield that he will be in Chicago indefinitely, and is looking to pick up some shifts and keep his skills up. She agrees, after finding out that one of his teachers at the hospital was Mark Greene. While there, Carter is reunited with several familiar faces, including Morris, Jerry, Neela, Zadro and Sam Taggart. Sam passes on that she's heard from Abby and Kovac, and that they are doing well, while he explains to her that Kem is also fine and visiting her parents in Paris. He visits the Joshua Makaio Carter Center, taking time to clear snow accumulating on Joshua's name at the sign. At the end of the episode, it is shown that Carter is on dialysis. In the following episode "T-minus-6", it's revealed that this is because of amyloidosis developing from schistosomiasis which irreparably damaged Carter's remaining kidney (the other's function being lost when he was stabbed by Sobricki in the Season 6 episode "Be Still My Heart"). He is back in Chicago to be placed on the US transplant list. Working in the ER, he's shown to still be a good doctor with good judgement, but is not up on the latest medicines and techniques used in the U.S. In the episode "Old Times" he is visited by his mentor and good friend Peter Benton, to whom he reveals that his relationship with Kem is not doing well. In the same episode, he gets a new kidney.