To train for the 2020 Summer Olympics, he agreed to become a volunteer assistant coach for the Michigan Wolverines swimming and diving team in order to use the pool facilities during the COVID-19 pandemic.

[7][18] At the 2011 US National Championships, Hixon captured the senior men 1-meter springboard title at the UCLA's Spieker Aquatics Center in Los Angeles.

[20] Hixon qualified for his first senior international competition, the 2013 World Aquatics Championships in Barcelona, with Troy Dumais, and finished fifth in the men's 3-meter synchronized event.

[27] In the men's synchronized 3-meter springboard event, Hixon along with his diving partner Sam Dorman placed second and won the silver medal with a score of 450.21, behind Jack Laugher and Chris Mears of Great Britain (454.32) and ahead of the Chinese pair Qin Kai and Cao Yuan (443.70).

[30] Hixon and new partner Andrew Capobianco attended the 2019 World Aquatics Championships and placed eighth after the final round of the men's synchronized 3-meter springboard event, totaling 388.08.

However, Hixon and Capobianco were unexpectedly chosen to represent the United States at the 2021 FINA Diving World Cup after fellow American pair David Boudia and Steele Johnson abruptly pulled out eight days prior to the start of the competition.

[32][33] In June 2021, Hixon and Capobianco placed first in the United States Olympics diving trials for the men's synchronized 3-meter springboard event with a score of 1289.37.

[34] In the men's synchronized 3-meter springboard event, Hixon and Capobianco placed second and won the silver medal with a final score of 444.36, behind Wang Zongyuan and Xie Siyi of China (467.82), and ahead of Patrick Hausding and Lars Rüdiger of Germany (404.73).