Miller competed at her first Australian Senior National Championships in 2008 and finished 12th in the all-around.
In 2009, she finished 7th overall and 2nd on the uneven bars.

At the 2009 World Championships in London, she finished 5th in the uneven bars qualification and 7th in the finals.
At the 2010 Pacific Rim Championships, she finished 3rd with the Australian team, 8th on the uneven bars, and 19th in the all-around.

In June 2012, Miller was selected to represent Australia at the 2012 Summer Olympics in London.
At the Olympics, she finished 29th on bars, 42nd on floor, and 10th with the Australian team.

After her Olympic debut, Miller took some time out of the gym.
She resumed training in November 2014 at Waverley Gymnastics Centre in Melbourne.

Miller attended the 2014 Commonwealth Games in Glasgow, where she claimed a silver on uneven bars (behind British gymnast Rebecca Downie) and helped Australia earn a silver in the team competition.
Later that year, she competed in the 2014 World Artistic Gymnastics Championships in Nanning, China, where she qualified for the floor final in 8th place and finished 6th.

In June 2016, Miller was announced as Australia's lone representative in the women's gymnastics competition at the 2016 Olympics.

In 2017 Miller was a contestant in the first season of Australian Ninja Warrior.
Miller competed at her first Australian Senior National Championships in 2008 and finished 12th in the all-around. In 2009, she finished 7th overall and 2nd on the uneven bars.
At the 2009 World Championships in London, she finished 5th in the uneven bars qualification and 7th in the finals. At the 2010 Pacific Rim Championships, she finished 3rd with the Australian team, 8th on the uneven bars, and 19th in the all-around.
In June 2012, Miller was selected to represent Australia at the 2012 Summer Olympics in London. At the Olympics, she finished 29th on bars, 42nd on floor, and 10th with the Australian team.
After her Olympic debut, Miller took some time out of the gym. She resumed training in November 2014 at Waverley Gymnastics Centre in Melbourne.
Miller attended the 2014 Commonwealth Games in Glasgow, where she claimed a silver on uneven bars (behind British gymnast Rebecca Downie) and helped Australia earn a silver in the team competition. Later that year, she competed in the 2014 World Artistic Gymnastics Championships in Nanning, China, where she qualified for the floor final in 8th place and finished 6th.
In June 2016, Miller was announced as Australia's lone representative in the women's gymnastics competition at the 2016 Olympics.
In 2017 Miller was a contestant in the first season of Australian Ninja Warrior.
Larrissa Miller