A former trauma surgeon and clinical professor in Arizona, Carmona has been warning about the threat of bioterrorism since the mid-1990s.
He also has been busy as a sheriff's SWAT team member. A 1992 cliff-side rescue in which he took part inspired a made-for-television movie.
In 1999, he came upon a traffic accident that turned into a hostage situation.
"We find out after the fact that this is an individual who had just murdered his own father and who was en route to kill somebody else," said Pima County Sheriff Clarence Dupnik.
Carmona shot and killed the suspect, earning recognition as one of the nation's "10 Top Cops."
Carmona grew up in New York's Spanish Harlem section. His family was poor, and many of his friends became involved in a life of crime. Carmona dropped out of high school and enlisted in the Army at age 17 -- afraid that he might end up in prison, too, he said.
"I was fortunate. I went away to Vietnam," he said in a 1999 interview.
After earning two Purple Hearts and a Bronze Star, he became a doctor.
Carmona hit some bumps in his career after settling in Tucson, Arizona. As director of a trauma center there, he lost his job in a management reorganization. Carmona filed a breach of contract lawsuit and won.
He later resigned as administrator of the Pima County health system when financial troubles mounted. A Carmona spokesman said he left because he was not in control of the assets of the system but was held responsible for them.
Questions also have been raised about reports that it took him eight years to win board certification in his field, general surgery, and that he failed the exam twice, according to The Associated Press.
Some colleagues also have suggested he has a confrontational style that makes him difficult to work with.
But he remains popular in Arizona.
"Energetic, caring, productive, humorous and thoughtful" is how colleague Marie Swanson describes Carmona.
"He's got the character, he has the background, he has the inspirational skills, the motivational skills, the organizational skills," added Lt. Terry Parish of the Pima County Sheriff's Department.
If confirmed, Carmona would be the nation's second Hispanic surgeon general. The first, Antonia Novello, served in the first Bush administration.
