The Supreme Court jury took less than a day to condemn him for killing the 22-year-old while walking to her cleaning job.
He has been given a life sentence.
McEwan admitted that he had been assaulted, bombed and strangled in November 2013, but he did not plead guilty to murder on mental health grounds.
Members of her family hugged each other and cried when the verdict was pronounced.
Ms. Ban came to Australia to improve her English and realize her dream of becoming a microbiologist.
Through an interpreter outside the court, Ban's mother Suk Bun Jung spoke about her pain and the hole that had remained in her life and her heart.
"My Eunji, please help me, if I need to continue with nice memories of us, you must help me so that I can be strong enough to keep going," she said.
"(McEwan) can still see his family and parents and loved ones, but for us Eunji is gone forever – until we meet again in heaven, we will not be able to see our daughter."
McEwan claimed he was possessed by a demon when in the early hours of November 24, 2013, he was mrs. Ban attacked her department of Roma Street Parklands.
McEwan, who was diagnosed with schizophrenia after his arrest, told the court that he was trying, but he could not stop herself from attacking her.
However, three psychiatrists demonstrated during the trial that they did not believe that McEwan had the consequences of schizophrenia at the time of the murder.
"You knew what you were doing and you knew it was wrong," Judge Roslyn Atkinson said when he condemned him.
"Yet you gave in to your sadistic and violent fantasies and carried out this terrible crime."
Ban's father, Hyeong-Gyu Ban, said he could not bring himself to forgive McEwan.
"We came to court today to forgive him, we were prepared to forgive him," he said through an interpreter.
"But what we saw in court, the way he went through, we felt that it was just full of excuses. We have no real regrets, regret."
McEwan, from the suburb of Spring Hill, had been drinking with friends the night before killing, woke up the next day, and walked through the streets near Mrs. Ban's house.
He randomly attacked her before she could scream or fight back.
He dragged her body up the stairs to the nearby Wickham Park and dumped it by a tree, which he decorated with bushes of hair.
The process heard that Mrs. Ban was so badly beaten that she drowned in her own blood.
"You have decided to go out and kill someone," said Justice Atkinson.
"You … chose someone for no reason, apart [from] to act on your violent and sadistic tendencies and commit the most brutal, terrible crime. "
McEwan stays behind at least until the end of 2033, with time already served and a compulsory non-parole period of 20 years.