Chuck de Caro and his wife, former Headline News anchor and CNN correspondent Lynne Russell, were on a road trip and spending the night at an Albuquerque motel when de Caro killed the man during what Russell called an attempted robbery.
Albuquerque police said they have yet to question de Caro, who had surgery for his wounds.
Officer Fred Duran said no charges were expected to be filed against de Caro. Russell said her husband fired in self-defense.
"I am really proud of him," Russell said. "I thank him over and over for saving my life. He really is my hero."
Russell said the gunman came into their Motel 6 room through an open door after she had just returned from getting something out of the car. He pushed her into the room.
De Caro, who worked at CNN in the mid-1980s as special assignments correspondent, was coming out of the bathroom after taking a shower and saw Russell being held at gunpoint.
"He tried to change the guy's mind," Russell said.
The gunman wanted money and other valuables, she said.
She told him she would look in her purse to see what they had. She reached down and put into the purse one of two handguns the couple had in a side table. She gave the handbag to her husband.
Russell said the guns were legal, something police are still investigating.
The man's behavior was increasingly erratic, Russell said. He told them to get a briefcase he saw.
The couple explained there was nothing of value in the bag, Russell said, but the man lunged at them and "went around the bed and then opened fire on Chuck. There was a firefight inside the room."
De Caro was shot once in the leg and twice in the abdomen.
He fired all the rounds in the first handgun, then picked up the other and shot the man, whom police identified in a statement as the "offender in the altercation." He was found in the parking lot and later died at a hospital, CNN affiliate KOAT-TV
in Albuquerque reported.
Russell, who worked for Headline News (now HLN) from 1983 to 2001, said the couple was heading to California and, after stopping in Albuquerque to have dinner with friends, they decided to get a motel room. They chose Motel 6 because it allows dogs, she said.