Hackett's outlandish behaviour first made the headlines when he was accused of assaulting a passenger during a flight from Adelaide to Melbourne in April, 2016.
The man alleged Hackett grabbed him by the chest and "tweaked [his] nipple quite forcefully" before being restrained and questioned by Federal Police upon landing.
Hackett, however, maintains his innocence saying he never swore nor was he confrontational towards other passengers.
"I drank before that flight, got on that flight and there was one gentleman sitting in front of me," Hackett said.
"I was drunk for sure and he leaned his seat back so I tapped him on the shoulder to ask him to put his seat up a little bit – because I'm 6'6", a big guy.
"Did I touch his nipple? Look, if I did I didn't mean to, I certainly didn't mean to grab anyone inappropriately."
Hackett appeared to hit rock bottom once more in February this year after going missing from his parent's house on the Gold Coast after a drunken argument with his father.
After being reported missing, Hackett uploaded a now-infamous photo to Instagram of facial injuries allegedly inflicted by his brother Craig who had punched him in the face a month earlier.
"He came over to my house and I guess I was refusing that help and he tried to come in," Hackett said. "I didn't want him to come in, I just wanted to be on my own, and when I get into that state of mind I go reclusive."
"He wanted to come in, I didn't want him to come in, we were struggling through the door and then he won – he is a very strong guy.
"I was trying to push him out and we sort of got into a bit of push and shove and then he whacked me with his weak arm, so I would hate to see his strong arm.
"And then I ended up in hospital because of that and we were both very regretful for the situation," said Hackett.
Hackett called time on his swimming career after the 2008 Olympics before sensationally announcing he would be making a comeback for the 2015 World Championships, six and a half years after racing his last major competition.
Since quitting the sport, however – this time for good – Hackett revealed he struggles to bounce back from bouts of depression as easily as he used to.
"Any time I have gone through something I have fallen into that hole much quicker than I ever had through my swimming career, or any other phase in my life where I have felt challenges," he said.
"It's gotten to a point where it is so public and so hard to deal with and has crushed me so much and got me so low that I actually needed to get a team around me to fix that and to have the strategies in place to look after myself properly."
Hackett also told the radio hosts that his biggest fear is when his children, aged seven, start searching his name on the internet.
"There are a lot of good things, there's a lot of achievements there but on the flip side of that there has been a lot of public controversy, things that I have gone through.
"Sensationalist headlines, lies and inaccuracies and things that I will have to explain one day," Hackett said. "Like I want to go out there and be depressed and drink myself stupid and become self destructive.”
So is the rollercoaster ride finished for Grant Hackett? Possibly not.
As he told Men’s Health in a candid interview before the Rio Games last year, “It might be the nature of my personality. Or it might be I’m drawn to things that are extremely challenging and those challenges bring with them ups and downs. Maybe that’s what it’s always going to be like.”
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