And some viewers were floored when Chris was announced as the winner with some claiming it was unfair that he was even allowed to compete on the show given his brother, Guy Sebastian was a coach.
"That's rigged," wrote one person on Twitter. "Family members and friends of the judges should NOT be allowed to compete. complete nepotism and cronyism."
As upset as some viewers were, the winner of The Voice was determined by votes from the public.
Voting closed after all four artists had performed twice during the grand finale.
"It's upsetting to see the harsh reaction of everyone," a fan wrote on Twitter. "It might appear almost predictable that Chris would win but that's who the public voted for … not to mention he most certainly was a worthy winner!"
Another added: "People saying it's rigged? How? It was based on a public vote. Congrats to Chris!"
As part of the win, Chris pocketed A$100,000 and a recording contract with EMI Music Australia.
Guy Sebastian paid tribute to his brother during the finale: "I've just watched you grow and just stand on your own two feet during this show.
"Every time you've performed on the show, it's insanely good and I mean that not just as a brother, but as a Coach and as a fan."
The Voice crown will hopefully allow Chris to establish himself as a solo artist and no longer just be seen as "Guy's brother".
Last week he opened up to news.com.au about how hard it has been at times having such a famous brother.
"For me, I'm so proud and so honoured that he's [Guy's] done well," Chris said. "And then there's the other side of it where, before this season of The Voice, it didn't matter what I did, I was always seen as the brother first, which hurts. That's the truth.
"I've been doing it [music] a long time and I've tried to prove myself as much as I can and for the most part I've always been the brother and that's kind of sucked. I'd be lying if I said it didn't.
"That's why I've loved this season of The Voice. It's really given me an identity, even if other people didn't get to see that, I got to see it for myself which I'm incredibly grateful for."
Chris told news.com.au that before appearing on The Voice this year, he was contemplating giving up on his dreams of a solo career.
"I'm the front man for Peking Duk so I've been touring and singing their songs," he said. "I also play a million different pubs.
"When I say the words 'I was close to giving up', I was close to giving up on Chris Sebastian as an artist. I've been writing songs for a really long time and everybody seems to like my songs but when it came to the finish of 'let's do a deal', I couldn't get anything in Australia."
Chris said he had almost resigned himself to the fact his career would be "doing music, but doing other people's stuff".
"That was a legitimate fear of mine," he said. "I was definitely at that giving up point."
