"In recent days my name has been sullied in the media," Thierry Costa wrote in the note before committing suicide just over a week after the death of 25-year-old Gerald Babin on a remote Cambodian island.
Costa, 38, complained of "unfair accusations" against him in the note obtained from Media Medic, the subcontractor that provided the doctor for the hugely popular "Koh Lanta" series by Adventure Line Productions (ALP).
Costa had been Koh Lanta's emergency physician for four seasons, ALP said in a statement, adding: "Everyone admired his great professionalism with the participants and the production staff."
Babin died of a heart attack on the first day of filming on the tropical island of Koh Rong on March 22nd, prompting French broadcaster TF1 to axe the show's 2013 season, its 16th.
It was the first death in any French reality TV programme.
Costa said in his handwritten suicide note that he was "sure of having treated Gerald in a respectable way, as a patient and not as a contestant."
He added: "Even though I regret this unhappy end, I acted in conformity with the Hippocratic Oath."
ALP said Costa administered emergency care to Babin when he complained of cramps during one of the challenges set for contestants before the contestant was airlifted to hospital in nearby Sihanoukville, where he died.
French authorities have opened a preliminary inquiry into "involuntary homicide" to determine the cause of death, although the Cambodian authorities have determined that Babin died of natural causes.