[5] At the 2005 Australian Junior Championships, Mitchell finished seventh in the all-around, balance beam, and floor exercise and eighth on the uneven bars.

[6] She was selected to compete at the World Championships alongside Daria Joura, Shona Morgan, Hollie Dykes, and Chloe Sims, and they finished eleventh in the qualification round.

[6] Her final competition of the season was the Olympic Test Event, where she won the silver medal on the balance beam and placed fourth in the all-around.

[10] Mitchell competed at the Pacific Rim Championships where the Australian team finished fourth behind the United States, Canada, and China.

[12] In May, she competed at the Australian Championships where she finished fourth in the all-around, and she helped Western Australia win the silver medal in the team competition behind Victoria.

She also placed seventh on the uneven bars, won the silver medal on the balance beam behind Shona Morgan, and finished fourth on the floor exercise.

[13][14] Mitchell was selected to represent Australia at the 2008 Summer Olympics alongside Georgia Bonora, Ashleigh Brennan, Daria Joura, Shona Morgan, and Olivia Vivian.

[15] After the Olympics, she competed at the Stuttgart World Cup and won the silver medal on both the balance beam and the floor exercise.

[7][15] In July, Mitchell competed at the Australian Championships in Perth and claimed her first national all-around title with a total score of 112.325.

[20][21] She went on to win two silver medals in the event finals, on the floor exercise behind Great Britain's Beth Tweddle and on the balance beam behind China's Deng Linlin.

[7] After recovering from her broken hand, Mitchell sprained her ankle on a tumbling pass in March, and then strained her adductor in July, which ultimately caused her to miss the Australian Championships.

[6] On 5 March, Mitchell competed at the American Cup in Jacksonville, Florida where she finished sixth in the all-around with a total score of 54.932.

[38] In July, Mitchell won gold medals in the all-around, vault, balance beam, and floor exercise at the Australian Championships.

[39][40] She was then selected for the World Championships team alongside Ashleigh Brennan, Larrissa Miller, Emily Little, Georgia-Rose Brown, and Mary-Anne Monckton.

[51] Their Olympic training preparations included learning how to deal with flash photography with strobe lighting used at practice and being exposed to distracting noises.

[22][52] On 21 June 2012, she was formally named to represent Australia at the 2012 Summer Olympics alongside Georgia Bonora, Ashleigh Brennan, Emily Little, and Larrissa Miller.

[60][61] At the Commonwealth Games, Mitchell won a silver medal with the Australian team and on the floor exercise behind Claudia Fragapane.

[64] Mitchell competed at the 2015 Australian Championships and won the gold medal on the floor exercise and placed fourth on the balance beam.

[66][67] Mitchell returned to competition at the 2016 Australian Championships and was inducted into Gymnastics Australia's Hall of Fame after the qualification round.