Aaron Ashby competed at Cooperstown Dreams Park with the KC Royals (MO) in 2011, Tournament 5.

Aaron graduated from Park Hill High School (Kansas City, MO). A pitcher for his varsity baseball team, Aaron continued his education and baseball career at Crowder College (Neosho, MO). After his freshman year, he was selected by the Texas Rangers in the 2017 Major League Baseball draft but opted to continue his collegiate career. Aaron compiled a two-year record of 11-2 from the mound with a 2.29 ERA.

During the 2018 Major League Baseball draft, the Milwaukee Brewers drafted Aaron, he decided to transition to the professionals. He made his Major League debut on June 30, 2021 and helped the Brewers clinch the 2025 National League Central division.