Gerald Deehan, 58, said his family was fortunate to be alive after two masked men entered their Margaret Street home on Tuesday night.
Mr Deehan said shots were fired at him and his son Ryan, 30, who is undergoing surgery after he was shot in the foot.
Police are treating the incident as attempted murder.
Mr Deehan, who was unharmed, said he was in the kitchen when one of the gunmen came in.
“He shot straight away, straight through my trouser leg,” he said.
“As I stepped back, he fired another shot.”
Mr Deehan said his son was shot as he tried to stop the gunmen going upstairs to his other sons.
Mr Deehan’s daughter, Amanda, died in January.
The 34-year-old mother of two was addicted to prescription and counterfeit drugs.
“Their main reason for trying to shoot me dead was because I spoke out and my wife spoke out,” he said.
His wife Christine, who was also in the house at the time of the attack, said she would not be deterred by “drug-dealing scumbags”.
“This is my message for you,” she said.
“I will not shut up.
“I will give every one of your names.
“I will not stop my fight until I get the drug dealing scum off this earth that killed my daughter”.
Parish priest Fr Michael Canny said that people could not “act as judge and executioner” and the PSNI should be the “only law and order”.“No matter what issues are at the root of this attack, in any right-thinking society, we cannot have people taking the law into their own hands,” he added.
SDLP councillor Martin Reilly described the shooting as “horrific”.
“This type of violence is not wanted anywhere in the city and region,” he said.
Sandra Duffy, chair of the Derry and Strabane Policing and Community Safety Partnership, said it was clear the criminal gangs responsible had absolutely no concern for local people.
“Their only aim is to try to exert some sort of coercive control over the people living in these areas,” she said.
Police have appealed for anyone with information to come forward.
Detective Inspector Michael Winters said: “Two men, aged 30 and 58, were in their home in Margaret Street when two masked man entered the property at around 8:45pm.
“One of the masked men, armed with what has been described as a handgun, shot at the man aged in his fifties who was in the kitchen. Fortunately he wasn’t physically injured.
“However, as the 30-year-old occupant attempted to flee, he was shot at and sustained an injury to his foot, for which he is receiving medical treatment for in hospital.
“Both suspects then fled, possibly in a car.
“The gunman is described as being of medium to heavy build, and had his face covered.“The second suspect is described as being of a thinner build.
“We are working to establish a motive for what was a merciless attack.
“There is absolutely no justification for this type of brutality, and it is only by sheer luck that we are not dealing with a tragic situation today.
“There were three other occupants in the house at the time of the attack, a woman and two other males, and they have all been left extremely shaken by what took place in their home, somewhere they rightly deserve to feel safe.
“I want to appeal to anyone who was in Margaret Street between 8:40pm and 8:50pm on Tuesday night.
“Did you see anything you believe may be connected to what happened – any suspicious vehicles, or people acting suspiciously.
“If you have information you believe can assist our investigation, call our detectives at Strand Road on 101 quoting reference number 1838 08/10/19 and tell us what you know.
“Information can also be given anonymously through the independent charity Crimestoppers on 0800 555 111.”