He later played three seasons of college baseball at the University of California, Irvine, earning conference accolades and spending time with the United States collegiate national team in the offseason.

Hiura forwent his final year of college eligibility and signed with the Brewers after they selected him in the first round of the 2017 Major League Baseball draft.

In the following three seasons, Hiura's statistics regressed, including a National League (NL)-leading 85 strikeouts in 2020 and a .168 batting average in 2021.

[3] Undrafted out of high school, Hiura played college baseball at University of California, Irvine for the Anteaters.

[10] He signed and was assigned to the Arizona Brewers of the Rookie-level Arizona League, and after batting .435 with four home runs, 18 RBIs and a 1.339 OPS in 15 games, was promoted to the Wisconsin Timber Rattlers of the Single-A Midwest League where he finished the season, posting a .333 batting average with 15 RBIs and seven walks in 27 games.

[18] On June 3, 2019, despite a strong showing in the majors, Hiura was sent back down to Triple-A to the San Antonio Missions in order to make room for Travis Shaw.

On July 28, Hiura homered in the bottom of the 10th inning against the Chicago Cubs for his first career walk-off hit.

[20] On January 13, 2023, Hiura agreed to a one-year, $2.2 million contract with the Brewers, avoiding salary arbitration.

[21] On March 25, the Brewers announced that Hiura, who was out of options, did not make the Opening Day roster.

[26] In 49 games with Triple-A Toledo Mud Hens, he hit .232/.312/.401 with 6 home runs and 24 RBI.