As a junior, Montgomery committed to play college baseball at Indiana University.[8][9] He also would have been a preferred walk-on for the Indiana Hoosiers men's basketball team.[10] In 2021, his senior baseball season, he batted .333 with seven home runs, 23 RBIs, and 24 stolen bases, and led Southridge to their first ever IHSAA state championship.[11][12] Following the end of the season, he traveled to Cary, North Carolina, where he participated in MLB's first ever Draft Combine.[13]
Montgomery was assigned to the Kannapolis Cannon Ballers of the Single-ACarolina League to begin the 2022 season.[19] He was promoted to the Winston-Salem Dash of the High-ASouth Atlantic League in late June.[20] Montgomery was promoted once again in mid-August to the Birmingham Barons of the Double-ASouthern League.[21] Over 96 games between the three teams, he slashed .274/.381/.429 with 11 home runs, 47 RBI, and 17 doubles.[22] He opened the 2023 season on the injured list with oblique and back injuries.[23] Montgomery returned to play early June, playing ten games with the Arizona League White Sox before being assigned to the Dash.[24] In late July, he was promoted to Birmingham.[25] Over 64 games, he batted .287 with eight home runs and 37 RBI.[26] After the season, he was selected to play in the Arizona Fall League for the Glendale Desert Dogs.[27]
Montgomery was assigned to the Charlotte Knights of the Triple-AInternational League to open the 2024 season.[28] In 130 games, he slashed .214/.329/.381 with 18 home runs, 63 RBI, and eight stolen bases. On November 19, 2024, the White Sox added Montgomery to their 40-man roster to protect him from the Rule 5 draft.[29]