Thomas Jackson, 30, of Congleton, Cheshire, was injured as he tried to help Mia Ayliffe-Chung, 20, in the attack at a hostel last week.
Frenchman Smail Ayad, 29, has been charged with murdering Ms Ayliffe-Chung and attempting to murder Mr Jackson.
Police said this charge would be changed to murder.
Latest updates on backpacker's death
Mr Jackson's father Les said: "We are bereft. Our darling Tom has left us and the world is a poorer place.
"There is dark and evil in this world perpetrated by a few, but so much more love and light emanates from so many more. That thought will sustain us over the coming days."
The backpacker suffered head injuries as he went to the aid of Ms Ayliffe-Chung, from Wirksworth, Derbyshire. Police described his actions as "selfless".
A spokesman for Queensland Police said Mr Jackson died in the Townsville Hospital.
Investigations are continuing, but detectives will upgrade the charge to murder when Mr Ayad next appears at Townsville Magistrates' Court on October 28, he added.
Mr Ayad is alleged to have stabbed Ms Ayliffe-Chung and to have caused the injuries which led to Mr Jackson's death at the Shelley's Backpackers accommodation in Home Hill on 23 August, at about 23:15 local time.
Twelve police officers were also injured.
Police previously said they were investigating whether Mr Ayad had an "obsession" with Ms Ayliffe-Chung.
Mr Jackson's family said they were "immensely proud" of him for his actions.
"There are many and varied reasons why we are, and always will be, immensely proud of Tom," his father said.
"His actions in response to this horrific attack only add to that sense of pride."
Mr Jackson's sister, Liv, wrote on Facebook: "There is nothing in this world that can prepare you for the pain and heartbreak of losing a sibling and a friend, but there is great comfort in knowing that he was mine.
"All that I ask is that you don't remember Tom as a victim.
"Indescribably proud of everything you accomplished and the lives you touched. I will love you always and forever TJ, your little sister, Lou."
Rachel Edwards, 30, from Crewe, Cheshire, who has been close friends with Mr Jackson since they studied at South Cheshire College together, said there would "never be another one like him".
She said: "He would literally try his utmost to try and light people's lives up with his kind words and inspiration, always pointing out the best in you."
A fundraising page set up by Mr Jackson's friend Shoshana Palatnik has reached half of its Â£10,000 target to help his family.
Ms Palatnik initially set up the Youcaring fundraising page for medical costs while Mr Jackson was on life support.
A "selfless" backpacker who was injured trying to save another traveller as she was stabbed to death in Australia has died, police in Queensland have said.