[2][4] He is the son of Jeff Julian, who was a U.S. National Team member, and Kristine Quance, a gold medalist in swimming at the 1996 Summer Olympics.

[10] At the 2021 NCAA Championships, Julian placed third in the 200 yard freestyle with a 1:31.55, finishing behind Kieran Smith and Drew Kibler.

[11][13] At the 2020 US Olympic Trials in Omaha, Nebraska and held in 2021 due to the COVID-19 pandemic, Julian did not start the 400 meter freestyle on the first day of competition in the prelims heats.

[16] On the third day of competition, Julian ranked third in the prelims heats of the 200 meter butterfly with a time of 1:56.42, advancing to the semifinals.

[21] The next day Julian started competition in the morning, tying for second-rank overall in the prelims heats of the 100 meter butterfly behind Caeleb Dressel with a time of 51.71 seconds.

[24] Day seven, Julian concluded competition with the final of the 100 meter butterfly where he tied Coleman Stewart for fourth place with a time of 51.78 seconds.

[26] Later in the championships, Julian swam a personal best time in the 200 meter individual medley with a 1:57.86, which made him the fifth fastest American in the event for 2021 behind Michael Andrew, Chase Kalisz, Carson Foster, and Kieran Smith.

[28] In the final of the 200 meter butterfly, Julian finished less than two tenths of a second behind bronze medalist Chad le Clos of South Africa with a time of 1:50.01 to place fourth.

[48] He swam a 1:31.71 in the prelims heats of the 200 yard freestyle on day three and qualified for the evening final ranking fourth.

[54] On the morning of the first day of the 2022 US International Team Trials in Greensboro, North Carolina, Julian swam a personal best time of 1:54.34 in the prelims heats of the 200 meter butterfly to qualify for the final ranking first.

[56] The following morning, he ranked third in the prelims heats of the 200 meter freestyle with a personal best time of 1:46.76 and qualified for the evening final.

[64] The third day of pool swimming competition at the Championships, June 20, Julian ranked fourth in the preliminaries of the 200 meter butterfly with a time of 1:55.04, qualifying for the evening semifinals.

[72] The following month, Julian was named to the USA Swimming team roster for the 2022 Duel in the Pool, held competing against Australia in August.

[74][76] Julian improved upon his personal best time in the 100 meter individual medley at the 2022 FINA Swimming World Cup stop in late October in Toronto, Canada, his first FINA Swimming World Cup, lowering the mark to a 52.61 in the preliminary heats of the event to qualify for the evening final ranking first.

[80] Later in the same session he won the gold medal in the 200 meter butterfly with a personal best time of 1:49.69, which was 0.09 seconds faster than silver medalist Chad le Clos.

[81] Day three of three, he won the silver medal in the 200 meter freestyle with a personal best time of 1:42.35, finishing 0.03 seconds behind gold medalist and fellow American Brooks Curry.

[86] Day three of six, Julian started off with a new Australian All Comers record of 1:49.93 in the preliminaries of the 200 meter butterfly and qualified for the final ranking first.

[96][97] For his final event, the 4×100 meter medley relay on day six of six, he split a 49.12 for the butterfly leg in the preliminaries, contributing to a first-ranked final-qualifying time of 3:23.65.